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Students can Download Tamil Nadu 12th Chemistry Model Question Paper 3 English Medium Pdf, Tamil Nadu 12th Chemistry Model Question Papers helps you to revise the complete Tamilnadu State Board New Syllabus and score more marks in your examinations.

TN State Board 12th Chemistry Model Question Paper 3 English Medium

Instructions:

1. The question paper comprises of four parts
2. You are to attempt all the parts. An internal choice of questions is provided wherever: applicable
3. All questions of Part I, II, III and IV are to be attempted separately
4. Question numbers 1 to 15 in Part I are Multiple choice Questions of one mark each.  These are to be answered by choosing the most suitable answer from the given four alternatives and writing the option code and the corresponding answer
5. Question numbers 16 to 24 in Part II are two-mark questions. These are lo be answered in about one or two sentences.
6. Question numbers 25 to 33 in Part III are three-mark questions. These are lo be answered in about three to five short sentences.
7. Question numbers 34 to 38 in Part IV are five-mark questions. These are lo be answered in detail. Draw diagrams wherever necessary.

Time: 3 Hours
Maximum Marks: 70

Part-I

Answer all the questions. Choose the correct answer. [15 × 1 = 15]

Question 1.
Gibbs free energy change for the electrolysis process is expressed by
(a) ∆G° = – nFE°
(b) ∆G° = – nF
(c) ∆G° = – nE°
(d) ∆G° = nFE°
Answer:
(a) ∆G° = – nFE°

Question 2.
Match items in column -II with the items of column – II and assign the correct code.

Answer:
(a)
A – 2
B – 1
C – 4
D – 3

Question 3.
Shape of ClF₃ is  ……………..
(a) Linear
(b) T-shape
(c) Pyrimidal
(d) Square planar
Answer:
(b) T-shape

Question 4.
The catalytic behaviour of transition metals and their compounds is ascribed mainly due to ……………..
(a) their magnetic behaviour
(b) their unfilled d orbitals
(c) their ability to adopt variable oxidation states
(d) their chemical reactivity
Answer:
(c) their ability to adopt variable oxidation states

Question 5.
Which one of the following pairs represents linkage isomers?
(a) [CU(NH₃)₄] [PtCl₄] and [Pt(NH₃)₄] [CuCl₄]
(b) [CO(NH₃)₅(NO₃)]SO₄ and [CO(NH₃)₅(ONO)]
(c) [CO(NH₃)₄(NCS)₂]Cl and [CO(NH₃)₄(SCN)₂]Cl
(d) both (b) and (c)
Answer:
(c) [CO(NH₃)₄(NCS)₂]Cl and [CO(NH₃)₄(SCN)₂]Cl’

Question 6.
Each atom in the comer of the cubic unit cell is shared by how many unit cells?
(a) 8
(b) 6
(c) 1
(d) 12
Answer:
(a) 8

Question 7.
The rate constant of a reaction is 5.8 × 10^-2 s^-1 . The order of the reaction is ……………..
(a) First order
(b) zero order
(c) Second order
(d) Third order
Answer:
(a) First order
Solution:
The unit of rate constant is s”1 and it indicates that the reaction is first order.

Question 8.
The hydrogen ion concentration of a buffer solution consisting of a weak acid and its salts is given by…………………
(a) [H⁺] = \(\frac{\mathbf{K}_{\mathrm{a}}[\mathrm{a} \mathrm{cid}]}{[\mathrm{salt}]}\)
(b) [H⁺] = K_a[salt]
(c) [H⁺] = K_a[acid]
(d) [H⁺] = \(\frac{\mathrm{K}_{\mathrm{a}}[\mathrm{salt}]}{[\text { acid }]}\)
According to Henderson equation

Question 9.
Kohlrausch’s law is applied to calculate ……………..
(a) molar conductance at infinite dilution of a weak electrolyte
(b) degree of dissociation of weak electrolyte
(c) solubility of a sparingly soluble salt
(d) all the above
Answer:
(d) all the above

Question 10.
For freudlich isotherm a graph of \(\log \frac{x}{\mathrm{m}}\) is plotted against log P. The slope of the line and its y – axis intercept respectively corresponds to ………
(a) 1/n , k
(b) log 1/n ,k
(c) 1/n , log k
(d) log 1/n, log k
Answer:
(c) 1/n , log k
Solution:

Question 11.
]The reaction of sodium methoxide with ethyl bromide follows
(a) SN¹ mechanism
(b) SN² mechanism
(c) E₁ reaction
(d) E₂ reaction
Answer:
(b) SN² mechanism

Question 12.
In which of the following reactions new carbon – carbon bond is not formed?
(a) Aldol condensation
(b) Friedel craft reaction
(c) Kolbe’s reaction
(d) Wolf kishner reduction
Answer:
(d) Wolf kishner reduction

Question 13.
The reagent used to convert Nitromet’nane to methyl amine is
(a) Zn/NH₄Cl
(b) Sn/HCl
(c) H₂SO₅
(d) H₂S₂O₈
Answer:
(b) Sn/HCl

Question 14.
If one strand of the DNAhas the sequence ‘ATGCTTGA’, then the sequence of complementary
strand would be
(a) TACGAACT
(b) TCCGAACT
(c) TACGTACT
(d) TACGRAGT
Answer:
(a) TACGAACT

Question 15.
The ratio between the maximum tolerated dose of a drug and a minimum curative dose is called ……………..
(a) iso electric point
(b) therapeutic index
(c) critical point
(d) iso thermal point
Answer:
(b) therapeutic index

Part – II

Answer any six questions. Question No. 20 is compulsory. [6 × 2 = 12]

Question 16.
Describe the role of Sodium cyanide in froth floatation.
Answer:

• Sulphide ores are concentrated by the froth floatation process.
• Depressants are used to prevent certain type of particles from forming the froth.
• NaCN act as a depressant to separate ZnS from PbS.

Question 17.
Which is more stable? Fe³⁺ or Fe²⁺ – explain.
Fe (Z = 26) Fe → Fe²⁺ + 2e^–
Fe → Fe³⁺ + 3e^–
Fe²⁺ [Number of electrons 24]
Electronic configuration = [Ar]3d⁶
Fe³⁺ [Number of electrons 23]
Electronic configuration = [Ar]3d⁵
Among Fe³⁺ and Fe²⁺, Fe³⁺ is more stable due to half filled d-orbital. This can be explained by Aufbau principle. Half filled and completely filled d-orbitals are more stable than partially filled d-orbitals. So Fe³⁺ is more stable than Fe²⁺ .

Question 18.
Write briefly about the applications of coordination compounds in volumetric analysis.
Answer:
Hardness of water is due to the presence of Ca²⁺ and Mg²⁺ions in water. EDTA forms stable complexes with Ca²⁺ and Mg²⁺ . So the total hardness of water can be estimated by simple volumetric titration of water with EDTA.

Question 19.
Classify the following solids
(a) P4 (b) Brass
(c) Diamond
(d) NaCl
(e) Iodine
Answer:
(a) P₄ – Molecular solid
(b) Brass – Metallic solid
(c) Diamond – Covalent solid
(d) NaCl – Ionic solid .
(e) Iodine – Molecular solid

Question 20.
A lab assistant prepared a solution by adding a calculated quantity of HC1 gas 25°C to get a solution with [H₃O⁺]= 4 × 10^-5 s M. Is the solution neutral (or) acidic (or) basic.
Answer:
[H₃O⁺] = 4 × 10^-55 M
pH = -log₁₀[H₃O⁺]
PH = – log₁₀ [4 × 10^-5]
pH = -log₁₀[4]-log_1o[10^-5]
pH = – 0.6020 – (-5) = – 0.6020 + 5
pH = 4.398
Therefore, the solution is acidic.

Question 21.
0.1M copper sulphate solution in which copper electrode is dipped at 25°C. Calculate the electrode potential of copper. [Given: E° _Cu²⁺|Cu = 0.341
Answer:
Given that
[Cu²⁺] = 0.1M
E° _Cu²⁺|Cu = 0.34
E_Cell = ?
Cell reaction is Cu²⁺(aq) + 2e^– → Cu (s)

Question 22.
Can we use nucelophiles such as NH3,CH₃O^– for the Nucleophilic substitution of alcohols
Answer:
Increasing order of nucelophilicity,

• Higher electron density will increase the nucelophilicity.
• Negatively charged species are almost always more nucelophiles than neutral species.
• ROe has an alkyl group attached, allowing a greater amount of polarizability. This means oxygen’s lone pairs will be more readily available to reach in \(\mathrm{RO}^{\ominus}\) than in \(\mathrm{OH}^{\ominus}\) . Hence CH₃O^– is the better nucelophile for the nucleophilic substitution of alcohols.
• NH₃ cannot act as nucelophile for the nucleophilic substitution of alcohols.

Question 23.
Aniline does not undergo Friedel – Crafts reaction. Explain.
Answer:
Aniline being a Lewis base reacts with Lewis acid AlCl₃ to form a salt.

Due to the presence of a positive charge on N-atom in the salt the group – NH₂ AlCl^– acts as a strongly deactivating group. As a result, it reduces the electron density in the benzene ring and which inhibits the electrophilic substitution reaction. Therefore aniline does not undergo Friedel – Crafts reaction.

Question 24.
What are hormones? Give examples.
Answer:
Hormone is an organic substance that is secreted by one tissue into the blood stream and induces a physiological response in other tissues. It is an inter cellular signaling molecule. Virtually every process is a complex organism is regulated by one or more hormones. Example, insulin, epinephrine, estrogen, androgen etc.

Part – III

Answer any six questions. Question No. 32 is compulsory. [6 × 3 = 18]

Question 25.
Write a note on zeolites.
Answer:
Zeolites:

• Zeolites are three dimensional crystalline solids containing aluminium, silicon and oxygen in their regular three dimensional framework.
• They are hydrated sodium alumino silicates with general formula.
  Na₂O.(Al₃O₃).x(SiO₂)y(H₂O)
  (x – 2 to 10; y = 2 to 6)
• Zeolites have porous structure in which the monovalent sodium ions and water molecules are loosely held.
• The Si and A1 atoms are tetrahederally coordinated with each other through shared oxygen atoms.
• Zeolites structure looks like a honeycomb consisting of a network of interconnected tunnels and cages.
• Zeolite crystal act as a molecular sieve. They help to remove permanent hardness of water.

Question 26.
What is Royal water? Mention its uses.
Answer:
When three parts of concentrated hydrochloric acid and one part of concentrated nitric acid are mixed, aquaregia is obtained. This is also known as Royal water. This is used for dissolving gold, platinum etc.
Au + 4H⁺ + NO₃^– + 4 Cl^– → AUCl₄^– + NO + 2H₂O
3Pt + 16H⁺ + 4NO₃^– + 18Cl^– → 3PtCl₃^2- + NO + 8H₂O

Question 27.
Ni(CN)₄]^2- is diamagnetic, while [NiCl₄]^2- is paramagnetic , explain using crystal field theory.
Answer:
(a) [Ni(CN)₄]^2-
Ni = 3d⁸ 4S²
Ni²⁺ = 3d⁸

• Nature of the complex – Low spin (Spin paired)
• Ligand filled electronic configuration of central metal ion, t⁶_2g e⁶_g
• Magnetic property : No unpaired electron (CN^– is strong filled ligand), hence it is diamagnetic.
• Magnetic moment : μ_s = 0

(b) [NiDl₄]^2-
Ni = 3d⁸ 4S²
Ni²⁺ = 3d⁸

• Nature of the complex, – high spin
• Ligand filled electronic configuration of central metal ion, t⁶_2g e²_g
• Magnetic property : Two unpaired electron (CF is weak field ligand). Hence it is paramagnetic
• Magnetic moment : μ_s= \(\sqrt{2(2+2)}\) = √8 = 2.83BM

Question 28.
Calculate the number of atoms per unit cell of bcc type.
Answer:

• In a body centered cubic unit cell, each comer is occupied by an identical particle and in addition to that one atom occupied the body centre.
• Those atoms which occupy the comers do not touch each other, however they all touch the one that occupies the body centre.
• Hence each atom is surrounded by eight nearest neighbours and coordination number is 8. An atom present at the body centre belongs to only a particular unit cell, i.e., unshared by other unit cell.

∴ number of atoms in a bcc unit cell = \(\frac{N_{c}}{8}+\frac{N_{b}}{1}=\frac{8}{8}=\frac{1}{1}\)
= 1 + = 2.

Question 29.
Identify the order for the following reactions
(i) Rusting of Iron
(ii) Radioactive disintegration of ₉₂U²³⁸
(iii) 2A + B → products ; rate = K[A]^1/2[B]²
Answer:
(i)
Theoritically order value may be more than one but practically one.
(ii) All radioactive disintegrations are first order reactions
(iii) 2 A + 3B → products
rate = K[A]^1/2[B]²
Order = \(\frac{1}{2}+2=\frac{5}{2}=2.5\)

Question 30.
Calculate the (i) hydrolysis constant, (ii) degree of hydrolysis and (iii) pH of 0.05M sodium carbonate solut
Answer:
(i) Hydrolysis constant:

Given Kw = 1 × 10^-14
c = 0.05M
pK_a = 10.26
pK = -log k_a
K_a = antilog of (-pK_a)
K_a = antilog of (-10.26)
K_a = 5.49 × 10^-11

Question 31.
Write the structure of the aldehyde, carboxylic acid and ester that yield 4 – methylpent -2-en-l-ol.
Answer:
(i) Aldehyde yield 4-methylpent-2-en-l-ol is,

(ii) Acid yield 4-methylpent-2-en-l-ol is,

(iii) Ester yield 4-methylpent-2-en-l-ol is,

The above shown compounds udergo reduction reaction to yield 4-methylpent-2-en-l-ol.

Question 32.
Predict the major product that would’ be obtained on nitration of the following compounds.

Answer:

Question 33.
What are the biological functions of nucleic acids?
Answer:

• Energy carriers (ATP)
• Components of enzyme cofactors. Example : Co enzyme A, NAD⁺, FAD
• Chemical messengers. Example : Cyclic AMP, CAMP

Part – IV

Answer all the questions. [5 × 5 = 25]

Question 34.
(a) (i) Explain the observations from the Ellingham diagram. (3)
(ii) Write a short note on anamolous properties of the first element of p-block. (2)
[OR]
(b) (i) Write the products formed in the reaction of concentrated nitric acid with zinc. (2)
(ii) d-block elements readily form complexes. Give reason. (3)
Answer:
(a) (i) 1. For most of the metal oxide formation, the slope is positive. It can be explained as follows.
Oxygen gas is consumed during the formation of metal oxides which results in the decrease in randomness. Hence, ∆S becomes negative and it makes the term, T∆S positive in the straight line equation.

2. The graph for the formation of carbon monoxide is a straight line with negative slope. In this case ∆S is positive as 2 moles of CO gas is formed by the consumption of one mole of oxygen gas. It indicates that CO is more stable at higher temperature.

3. As the temperature increases, generally ∆G value for the formation of the metal oxide become less negative and becomes zero at a particular temperature. Below this temperature, ∆G is negative and the oxide is stable and above this temperature ∆G is positive. This general trend suggests that metal oxides become less stable at higher temperature and their decomposition becomes easier.

4. There is a sudden change in the slope at a particular temperature for some metal oxides like MgO, HgO. This is due to the phase transition (melting or evaporation).

(ii) In p-block elements the first member of each group differs from the other elements of the corresponding group. The following factors are responsible for this anomalous behaviour.

• Small size of the first member.
• High ionisation enthalpy and high electronegativity.
• Absence of d-orbitals in their valance shell.

The first member of the group-13, boron is a metalloid while others are reactive metals. Moreover, boron shows diagonal relationship with silicon of group 14. The oxides of boron and silicon are similar in their acidic nature.

[OR]

(b) (i) Zinc with Cone.

(ii) 1. Transition elements (d-block elements) have a tendency to form coordination • compounds (complexes) with a species that has an ability to donate an electron pair to
form a coordinate covalent bond.

2. Transition metal ions are small and highly charged and they have vacant low energy orbitals to accept an electron pair donated by other groups. Due to these properties, transition metals form large number of complexes.

3. Examples: [Fe(CN)₆]^4- , [CO(NH₃)₆]³⁺

Question 35.
(a) (i) Write the IUPAC names for the following complexes. (2)
1. Na₂[Ni(EDTA)]
2. [CO(en)₃]₂(SO₄)₃
(ii) What is meant by piezo electricity? (3)
[OR]
(b) (i) Consider the oxidation of nitric oxide to form NO₂ (3)
2NO_(g) + O_2(g) 2NO_2(g)
(a) Express the rate of the reaction in terms of changes in the concentration of NO, O₂ and NO ₂
(b) At a particular instant, when [O₂]is decreasing at 0.2 mol L^-1s^-1 at what rate is [NO₂] increasing at that instant?
(ii) Classify the following as acid (or) base using Arrhen ¡us concept (2)
1. HNO₃ 2. Ba(OH)₂ 3. H₃PO₄ 4. CH₃COOH
Answer:
(a) (1) 1. Na₂[Ni(EDTA)] = Sodium Ethylenediaminetetraacetatonickelate (Il) (or)
Sodium 2,2′,2”,2”’-(ethane- I ,2-diyldinitrilo) tetraacetatonickelate(II)
2. [CO(en)₃]₂(SO₄)₃ = tris(ethylenediamine)cobalt(III) sulphate

(ii) Piezo electricity is the appearance of an electrical potential across the sides of a crystal. When you subject it to mechanical stress. The word piezo electricity means electricity resulting from pressure and latent heat. Even the inverse is possible which is known as inverse piezo electric effect.

(b) (i)

(ii) 1. HNO₃ : Nitric acid, dissociates to give hydrogen ions in water. .. HNOS is acid.
2. Ba(OH)₂ : Barium hydroxide, dissociates to give hydroxyl ions in water.
∴ Ba(OH)₂ is base.
3. H₃PO₄: Orthophosphoric acid, dissociates to give hydrogen ions in water.
∴ H₃PO₄ is acid.
4. CH₃COOH : Acetic acid, dissociates to give hydrogen ions in water.
∴ CH₃COOH is acid.

Question 36.
(a) Derive an expression for Nernst equation. (5)
[OR]
(b) Describe adsorption theory of catalysis. (5)
(a) Nernst equation is the one which relates the cell potential and the concentration of the specie:
involved in an electrochemical reaction.
Let us consider an electrochemical cell for which the overall redox reaction is,
xA+yB ⇌ lC+mD
The reaction quotient Q is,

We know that,
∆G = ∆G°+RT In Q ……..(1)
∴ ∆G = -nFE_cell ;∆G°=-nFE°_cell
∴ equation (1) becomes
– nFE_cell = nFE°_cell + RT lnQ ………(2)
Substitute the Q value in equation (2)

This is called the Nernst equation.
At 25°C (298 K) equation (4) becomes,

[OR]

(b) Adsorption theory:
Langmuir explained the action of catalyst in heterogeneous catalysed reactions based on adsorption. The reactant molecules are adsorbed on the catalyst surfaces, so this can also be called as contact catalysis.
According to this theory, the reactants are adsorbed on the catalyst surface to form an activated complex which subsequently decomposes and gives the product.
The various steps involved in a heterogeneous catalysed reaction are given as follows:

• Reactant molecules diffuse from bulk to the catalyst surface.
• The reactant molecules are adsorbed on the surface of the catalyst.
• The adsorbed reactant molecules are activated and form activated complex which is decomposed to form the products.
• The product molecules are desorbed.
• The product diffuse away from the surface of the catalyst.

Advantages of adsorption theory:
The adsorption theory explains the following

• Increase in the activity of a catalyst by increasing the surface area. Increase in the surface area of metals and metal oxides by reducing the particle size increases the rate of the reaction.
• The action of catalytic poison occurs when the poison blocks the active centres of the catalyst.
• A promoter or activator increases the number of active centres on the surfaces.

Question 37.
(a) (i) What is the major product obtained when two moles of ethyl magnesium bromide is treated with methyl benzoate followed by acid hydrolysis. (3)
(ii) What are essential and non-essential amino acids? Give one example of each type. (2)
[OR]
(b) How are the following conversions effected (5)
1. propanal into butanone
2. Hex-3-yne into hexan-3-one
3. phenylmethanal into benzoic acid
4. phenylmethanal into benzoin
Answer:
(a)

(ii) Essential amino acids: Amino acids which are not synthesised by the human body are called essential amino acids. Example: Valine, Leucine.
Non-essential amino acids: Amino acids which are synthesised by human body are called non-essential amino acids. Example: Glycine, Aspartic acid, etc.

[OR]

(b) 1. Propanal into butanone:

2. Hex-3-yne into hexan-3-one:

3. Phenylmeihanal into benzoic acid:

4. Phenyl methanal into benzoin:

Question 38.
(a) Identify A to E in the following frequency. of reactions. (5)

[OR]
(b) (i) What are the biological importance of proteins? (3)
(ii) Name one substance which can act as both analgesic and antipyretic. (2)
(a)

[OR]

(b) (i) Proteins are the functional units of living things play vital role in all biological processes

• All biochemical reactions occur in the living systems are catalysed by the catalytic proteins called enzymes.
• Proteins such as keratin, collagen acts as structural back bones.
• Proteins are used for transporting molecules (Haemoglobin), organelles (Kinesins) in the cell and control the movement of molecules in and out of the cells (Transporters).
• Antibodies help the body to fight various diseases.
• Proteins are used as messengers to coordinate many functions. Insulin & glucagon controls the glucose level in the blood.
• Proteins act as receptors that detect presence of certain signal molecules and activate the proper response.
• Proteins are also used to store metals such as iron (Ferritin) etc.

(ii) Aspirin (acetylsalicylic acid) is a chemical substance which lowers body temperature (to normal) and also reduces body pain. Therefore it acts as both antipyretic and analgesic.

Students can Download Computer Science Chapter 12 Structured Query Language (SQL) Questions and Answers, Notes Pdf, Samacheer Kalvi 12th Computer Science Book Solutions Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 12th Computer Science Solutions Chapter 12 Structured Query Language (SQL)

Samacheer Kalvi 12th Computer Science Structured Query Language (SQL) Text Book Back Questions and Answers

PART – 1
I. Choose The Best Answer

Question 1.
Which commands provide definitions for creating table structure, deleting relations, and modifying relation schemes?
(a) DDL
(b) DML
(c) DCL
(d) DQL
Answer:
(a) DDL

Question 2.
Which command lets to change the structure of the table?
(a) SELECT
(b) ORDER BY
(c) MODIFY
(d) ALTER
Answer:
(d) ALTER

Question 3.
The command to delete a table is ……………………..
(a) DROP
(b) DELETE
(c) DELETE ALL
(d) ALTER TABLE
Answer:
(a) DROP

Question 4.
Queries can be generated using …………………….
(a) SELECT
(b) ORDER BY
(c) MODIFY
(d) ALTER
Answer:
(a) SELECT

Question 5.
The clause used to sort data in a database ……………………….
(a) SORT BY
(b) ORDER BY
(c) GROUP BY
(d) SELECT
Answer:
(b) ORDER BY

PART – II
II. Answer The Following Questions

Question 1.
Write a query that selects all students whose age is less than 18 in order wise?
Answer:
SELECT * FROM STUDENT WHERE AGE <= 18 ORDER BY NAME.

Question 2.
Differentiate Unique and Primary Key constraint?
Answer:
The unique constraint ensures that no two rows have the same value in the specified columns. Primary key constraint declares a field as a Primary key which helps to uniquely identify a record. The primary key is similar to unique constraint except that only one field of a table can be set as primary key.

Question 3.
Write the difference between table constraint and column constraint?
Column constraint:
Column constraint apply only to individual column.

Table constraint:
Table constraint apply to a group of one or more columns.

Question 4.
Which component of SQL lets insert values in tables and which lets to create a table?
Answer:
Insert values in tables – DML Create a table – DDL

Question 5.
What is the difference between SQL and MySQL?
Answer:
SQL-Structured Query Language is a language used for accessing databases while MySQL is a database management system, like SQL Server, Oracle, Informix, Postgres, etc. MySQL is a RDBMS.

PART – III
III. Answer The Following Questions

Question 1.
What is a constraint? Write short note on Primary key constraint?
Answer:
Constraints are used to limit the type of data that can go into a table. This ensures the accuracy and reliability of the data in the database. Constraints could be either on a column level or a table level.

Primary Key Constraint:
This constraint declares a field as a Primary key which helps to uniquely identify a record. It is similar to unique constraint except that only one field of a table can be set as primary key. The primary key does not allow NULL values and therefore a field declared as primary key must have the NOT NULL constraint.
Example showing Primary Key Constraint in the student table:
CREATE TABLE Student
(
Admno integer NOT NULL PRIMARY KEY, → Primary Key constraint
Name char(20)NOT NULL,
Gender char(l),
Age integer,
Place char(10),
);

Question 2.
Write a SQL statement to modify the student table structure by adding a new field?
Answer:
ALTER TABLE Student MODIFY Address char(25);

Question 3.
Write any three DDL commands
a. CREATE TABLE Command
Answer:
You can create a table by using the CREATE TABLE command.
CREATE TABLE Student
(Admno integer,
Name char(20), \
Gender char(1),
Age integer,
Place char(10),
);

b. ALTER COMMAND
The ALTER command is used to alter the table structure like adding a column, renaming the existing column, change the data type of any column or size of the column or delete the column from the table.
Alter table Student add address char;

c. DROP TABLE:
Drop table command is used to remove a table from the database.
DROP TABLE Student;

Question 4.
Write the use of Savepoint command with an example?
SAVEPOINT command
Answer:
The SAVEPOINT command is used to temporarily save a transaction so that you can rollback to the point whenever required. The different states of our table can be saved at anytime using different names and the rollback to that state can be done using the ROLLBACK command.
SAVEPOINT savepoint_name;
UPDATE Student SET Name = ‘Mini ’ WHERE Admno=105;
SAVEPOINT A;

Question 5.
Write a SQL statement using DISTINCT keyword?
Answer:
DISTINCT Keyword:
The DISTINCT keyword is used along with the SELECT command to eliminate duplicate rows in the table. This helps to eliminate redundant data. For Example:
SELECT DISTINCT Place FROM Student;
Will display the following data as follows :
SELECT * FROM Student;
Output
Place
Chennai
Bangalore
Delhi

PART – IV
IV. Answer The Following Questions

Question 1.
Write the different types of constraints and their functions?
Answer:
Type of Constraints
Constraints ensure database integrity, therefore known as database integrity constraints. The different types of constraints are :

(i) Unique Constraint
This constraint ensures that no two rows have the same value in the specified columns. For example UNIQUE constraint applied on Admno of student table ensures that no two students have the same admission number and the constraint can be used as:
CREATE TABLE Student
(
Admno integer NOT NULL UNIQUE, → Unique constraint
Name char (20) NOT NULL,
Gender char (1),
Age integer,
Place char (10),
);
The UNIQUE constraint can be applied only to fields that have also been declared as NOT NULL.
When two constraints are applied on a single field, it is known as multiple constraints. In the above Multiple constraints NOT NULL and UNIQUE are applied on a single field Admno, the constraints are separated by a space and at the end of the field definition a comma(,) is added. By adding these two constraints the field Admno must take some value ie. will not be NULL and should not be duplicated.

(ii) Primary Key Constraint
This constraint declares a field as a Primary key which helps to uniquely identify a record. It is similar to unique constraint except that only one field of a table can be set as primary key. The primary key does not allow NULL values and therefore a field declared as primary key must have the NOT NULL constraint.
Example showing Primary Key Constraint in the student table:
CREATE TABLE Student
(
Admno integer NOT NULL PRIMARY KEY, → Primary Key constraint
Name char(20)NOT NULL,
Gender char(I),
Age integer,
Place char(10),
);
In the above example the Admno field has been set as primary key and therefore will help us to uniquely identify a record, it is also set NOT NULL, therefore this field value cannot be empty.

(iii) DEFAULT Constraint
The DEFA ULT constraint is used to assign a default value for the field. When no value is given for the specified field having DEFAULT constraint, automatically the default value will be assigned to the field.
Example showing DEFAULT Constraint in the student table:
CREATE TABLE Student
(
Admno integer NOT NULL PRIMARY KEY,
Name char(20)NOTNULL,
Gender char(1),
Age integer DEFAULT = “17”, → Default Constraint
Place char(10),
);
In the above example the “Age” field is assigned a default value of 17, therefore when no value is entered in age by the user, it automatically assigns 17 to Age.

(iv) Check Constraint:
This constraint helps to set a limit value placed for a field. When we define a check constraint on a single column, it allows only the restricted values on that field. Example showing check constraint in the student table:
CREATE TABLE Student
(
Admno integer NOT NULL PRIMARY KEY
Name char(20)NOTNULL,
Gender char(1),
Age integer (CHECK<=19),
→ Check Constraint
Place char(10),
);
In the above example the check constraint is set to Age field where the value of Age must be less than or equal to 19.
Note
The check constraint may use relational and logical operators for condition.

(v) TABLE CONSTRAINT
When the constraint is applied to a group of fields of the table, it is known as Table constraint. The table constraint is normally given at the end of the table definition. Let us take a new table namely Studentl with the following fields Admno, Firstname, Lastname, Gender, Age, Place: CREATE TABLE Student 1
Admno integer NOT NULL,
Firstname char(20),
Lastname char(20),
Gender char(1),
Age integer,
Place char(10),
PRIMARY KEY (Firstname, Lastname) → Table constraint
);
In the above example, the two fields, Firstname and Lastname are defined as Primary key which is a Table constraint.

Question 2.
Consider the following employee table. Write SQL commands for the qtns.(i) to (v)?
Answer:

1. To display the details of all employees in descending order of pay.
2. To display all employees whose allowance is between 5000 and 7000.
3. To remove the employees who are mechanic.
4. To add a new row.
5. To display the details of all employees who are operators.

Output:

1. SELECT * FROM employee ORDER BY DESC;
2. SELECT * FROM employee WHERE ((allowance >= 5000) AND(allowance <= 7000));
3. DELETE FROM employee WHERE desig = “Mechanic”;
4. INSERT INTO employee(Empcode, Name, desig, pay, allowance) VALUES(‘M1006’, ‘RAM’, ‘Mechanic’,22000, 8000);
5. SELECT * FROM employee WHERE desig = ‘operator’;

Question 3.
What are the components of SQL? Write the commands in each? Components of SQL?
SQL commands are divided into five categories:
Answer:

a. Data Definition Language
The Data Definition Language (DDL) consist of SQL statements used to define the database structure or schema. It simply deals with descriptions of the database schema and is used to create and modify the structure of database objects in databases.
SQL commands which comes under Data Definition Language are:

b. Data Manipulation Language
A Data Manipulation Language (DML) is a computer programming language used for adding (inserting), removing (deleting), and modifying (updating) data in a database.
SQL commands which comes under Data Manipulation Language are :

c. Data Control Language:
A Data Control Language (DCL) is used for controlling privileges in the database SQL commands: GRANT, REVOKE

d. Transactional Control Language:
Transactional control language (TCL) is used to manage transactions i.e. changes made to the data in the database.
SQL commands: COMMIT, ROLLBACK, SAVEPOINT

e. Data Query Language:
The Data Query Language (DQL) have commands to query or retrieve data from the database.
SQL commands: SELECT.

Question 4.
Construct the following SQL statements in the student table –
(i) SELECT statement using GROUP BY clause.
(ii) SELECT statement using ORDER BY clause.

(i) GROUP BY clause
The GROUP BY clause is used with the SELECT statement to group the students on rows or columns having identical values or divide the table into groups. For example to know the number of male students or female students of a class, the GROUP BY clause may be used. It is mostly used in conjunction with aggregate functions to produce summary reports from the database.
The syntax for the GROUP BY clause is
SELECT <column-names> FROM <table-name> GROUP BY <column-name>HAVING condition];
To apply the above command on the student table :
SELECT Gender FROM Student GROUP BY Gender;
The following command will give the below given result:

SELECT Gender, count(*) FROM Student GROUP BY Gender;

(ii) ORDER BY clause
The ORDER RTclause in SQL is used to sort the data in either ascending or descending based on one or more columns.
1. By default ORDER BY sorts the data in ascending order.
2. We can use the keyword DESC to sort the data in descending order and the keyword ASC to sort in ascending order.
The ORDER BY clause is used as:
SELECT <column-name> [,<column-name>,….] FROM <table-name> ORDER
BY <column1>,<column2>, …ASC\ DESC;
For example :
To display the students in alphabetical order of their names, the command is used as
SELECT * FROM Student ORDER BY Name;
The above student table is arranged as follows :

Question 5.
Write a SQL statement to create a table for employee having any five fields and create a table constraint for the employee table?
Answer:
CREATE TABLE EMPLOYEE
(Empcode integer NOT NULL,
Name char(20),
desig char(20),
pay integer,
allowance integer,
PRIMARY KEY(Name, desig));

Practice Programs

Question 1.
Create a query of the student table in the following order of fields name, age, place and admno?
Answer:
CREATE TABLE Student(Name char(30), age integer, place char(30), admno integer)).

Question 2.
Create a query to display the student table with students of age more than 18 with unique city?
Answer:
SELECT * FROM student WHERE age >= 18 GROUP BY city.

Question 3.
Create a employee table with the following fields employee number, employee name, designation, date of joining and basic pay?
Answer:
CREATE TABLE employee(empNo integer, ename char(30), desig char(30), doj datetime, basic integer);

Question 4.
In the above table set the employee number as primary key and check for NULL values in any field?
Answer:
CREATE TABLE employee(empno integer NOT NULL PRIMARY KEY, ename char(30) NOT NULL, desig char(30), doj datetime, basic integer).

Question 5.
Prepare a list of all employees who are Managers?
Answer:
SELECT * FROM employee WHERE desig = ’Managers’.

Samacheer kalvi 12th Computer Science Structured Query Language (SQL) Additional Questions and Answers

PART – I
I. Choose the correct answer

Question 1.
The SQL was called as …………………….. in early 1970’s.
(a) squel
(b) sequel
(c) seqel
(d) squeal
Answer:
(b) sequel

Question 2.
SQL means ………………………..
Answer:
Structured Query Language

Question 3.
RDBMS Expansion ………………………
Answer:
Relational DataBase Management System

Question 4.
Expand ANSI ………………………
(a) American North South Institute
(b) Asian North Standard Institute
(c) American National Standard Institute
(d) Artie National Standard Institute
Answer:
(c) American National Standard Institute

Question 5.
ANSI Published SQL standard in the year ………………………..
(a) 1986
(b) 1982
(c) 1984
(d) 1989
Answer:
(a) 1986

Question 6.
The latest SQL was released in ……………………….
(a) 1987
(b) 1992
(c) 2008
(d) 2012
Answer:
(c) 2008

Question 7.
The latest SQL standard as of now is …………………….
Answer:
SQL 2008

Question 8.
Identify which is not a RDBMS package …………………….
(a) MySQL
(b) IBMDB2
(c) MS-Access
(d) Php
Answer:
(d) Php

Question 9.
A ……………………… is a collection of tables.
Answer:
database

Question 10.
CRUD means ……………………
(a) creative reasoning under development
(b) create read update delete
(c) create row update drop
(d) calculate relate update data
Answer:
(b) create read update delete

Question 11.
A …………………… is a collection of related data entries and it consist of rows and columns.
Answer:
table

Question 12.
……………………….. is the vertical entity that contains all information associated with a specific field in a table
(a) Field
(b) tuple
(c) row
(d) record
Answer:
(a) Field

Question 13.
A ………………………… is a horizontal entity in the table.
Answer:
record

Question 14.
DDL means …………………………
Answer:
Data Defnition Language

Question 15.
Match the following:
1. DDL – (i) Modify Tuples
2. Informix – (ii) Create Indexes
3. DML – (iii) MySQL
4. DCL – (iv) Grant
(a) 1-ii, 2-iii, 3-i, 4-iv
(b) 1-i, 2-ii, 3-iii, 4-iv
(c) 1-iv, 2-iii, 3-ii, 4-i
(d) 1-iv, 2-i, 3-ii, 4-iiii
Answer:
(a) 1-ii, 2-iii, 3-i, 4-iv

Question 16.
The SQL used in high level programming languages is ………………………….
Answer:
Embedded Data Manipulation Language

Question 17.
WAMP stands for ……………………….
Answer:
Windows, Apache, MySQ1 and PHP

Question 18.
To work with the databases, the command used is …………………….. database
(a) create
(b) modify
(c) use
(d) work
Answer:
(c) use

Question 19.
Which is used to serve live websites?
(a) WAMP
(b) SAMP
(c) DAMP
(d) TAMP
Answer:
(a) WAMP

Question 20.
How many components of SQL are there?
(a) 3
(b) 4
(c) 5
(d) 6
Answer:
(c) 5

Question 21.
Which among the following is not a WAMP?
(a) PHP
(b) MySQL
(c) DHTML
(d) Apache
Answer:
(c) DHTML

Question 22.
Which is used to define database structure or schema?
(a) DML
(b) DDL
(c) DCL
(d) DQL
Answer:
(b) DDL

Question 23.
Identify which is not a SQL DDL command?
(a) create
(b) delete
(c) drop
(d) truncate
Answer:
(b) delete

Question 24.
Which command changes the structure of the database?
(a) update
(b) alter
(c) change
(d) modify
Answer:
(b) alter

Question 25.
Identify which statement is given wrongly?
(a) DDL statement should specify the proper data type
(b) DDL should not identify the type of data division
(c) DDL may define the range of values
(d) DDL should define the size of the data item
Answer:
(b) DDL should not identify the type of data division

Question 26.
Identify which is wrong?
DML means
(a) Insertion
(b) Retrieval
(c) Modification
(d) alter
Answer:
(d) alter

Question 27.
How many types of DML commands are there?
(a) 1
(b) 2
(c) 3
(d) 4
Answer:
(b) 2

Question 28.
Pick the odd out
Insert, update, alter, delete
Answer:
alter

Question 29.
Grant and Revoke commands comes under ……………………..
(a) DML
(b) DCL
(c) DQL
(d) DDL
Answer:
(b) DCL

Question 30.
…………………….. is a DQL command
(a) select
(b) commit
(c) update
(d) delete
Answer:
(a) select

Question 31.
Which one restores the database to last commit state?
(a) commit
(b) Grant
(c) rollback
(d) save point
Answer:
(c) rollback

Question 32.
Which is used to query or retrieve data from a database?
(a) DQL
(b) DML
(c) DCL
(d) DCM
Answer:
(a) DQL

Question 33.
Variable width character string is given by the data type ……………………….
(a) char
(b) varchar
(c) dec
(d) real
Answer:
(b) varchar

Question 34.
If the precision exceeds 64, then it is
(a) float
(b) real
(c) float
(d) decimal
Answer:
(c) float

Question 35.
…………………… have special meaning in SQL
(a) keywords
(b) commands
(c) clauses
(d) arguments
Answer:
(a) keywords

Question 36.
…………………… are the values given to make the clause complete
Answer:
Arguments

Question 37.
Each table must have at least ………………………. column
(a) 1
(b) 2
(c) 3
(d) 4
Answer:
(a) 1

Question 38.
Which one of the following ensures the accuracy and reliability of the data in the database?
(a) Arguments
(b) constraints
(c) column
(d) clauses
Answer:
(b) constraints

Question 39.
How many types of constraints are there?
(a) 2
(b) 3
(c) 4
(d) 5
Answer:
(c) 4

Question 40.
The …………………….. constraint can be applied only to fields that have also been declared a NOT Null.
Answer:
unique

Question 41.
When two constraints are applied on a single field, it is known as ……………………….. constraints.
Answer:
multiple

Question 42.
Which key helps to uniquely identify the record in the table?
(a) unique
(b) primary
(c) secondary
(d) null
Answer:
(b) primary

Question 43.
Which constraint is used to assign a default value for the field?
(a) unique
(b) primary
(c) secondary
(d) default
Answer:
(d) default

Question 44.
The check constraint may use ………………….. operators for condition.
(a) relational
(b) logical
(c) both
(d) None of these
Answer:
(c) both

Question 45.
When the constraint is applied to a group of fields of the table, then it is ………………………. constraint.
(a) table
(b) column
(c) multiple
(d) primary
Answer:
(a) table

Question 46.
The …………………….. command is used to insert, delete and update rows into the table.
(a) DCL
(b) DML
(c) DTL
(d) TCL
Answer:
(b) DML

Question 47.
If the data is to be added for all columns in a table
(a) specifying column is optional
(b) specifying column is must
Answer:
(a) specifying column is optional

Question 48.
Find the wrong statement from the following delete command
(a) permanently removes one or more records
(b) removes entire row
(c) removes individual fields
(d) deletes the record
Answer:
(c) removes individual fields

Question 49.
The update command specifies the rows to be changed using the …………………….. clause.
(a) where
(b) why
(c) what
(d) how
Answer:
(a) where

Question 50.
Set keyword in update command is used to assign new data.
True / false
Answer:
True

Question 51.
Find the wrong one about alter command
(a) remove a column
(b) remove all columns
(c) rename a column
(d) delete row
Answer:
(d) delete row

Question 52.
The keyword …………………….. is used along with the select command to eliminate duplicate rows in the table.
Answer:
distinct

Question 53.
The ……………………. keyword in select command includes an upper value and a lower value.
Answer:
betweeen

Question 54.
How many types of sorting are there?
(a) 2
(b) 3
(c) 4
(d) 5
Answer:
(a) 2

Question 55.
The default sorting order is ……………………….
Answer:
ascending

Question 56.
……………………. clause is used to filter the records.
Answer:
where

Question 57.
The ……………………… clause is used to select the group of students on rows or columns having identical values.
Answer:
group by

Question 58.
Which is to count the records?
(a) +
(b) *
(c) =
(d) /
Answer:
(b) *

PART – II
II. Answer The Following Questions

Question 1.
Write note on RDBMS?
Answer:
RDBMS stands for Relational DataBase Management System. Orqcle, MySQL, MS SQL Server, IBM DB2 and Microsoft Access are RDBMS packages. RDBMS is a type of DBMS with a row-based table structure that connects related data elements and includes functions related to Create, Read, Update and Delete operations, collectively known as CRUD.

Question 2.
What does data manipulation means?
Answer:
By Data Manipulation we mean,

1. Insertion of new information into the database
2. Retrieval of information stored in a database.
3. Deletion of information from the database.
4. Modification of data stored in the database.

Question 3.
What are the 2 types of DML?
Answer:
The DML is basically of two types:
Procedural DML – Requires a user to specify what data is needed and how to get it. Non-Procedural DML – Requires a user to specify what data is needed without specifying how to get it.

Question 4.
What is meant by data type?
Answer:
The data in a database is stored based on the kind of value stored in it. This is identified as the data type of the data or by assigning each field a data type. All the values in a given field must be of same type.

Question 5.
Write about ALL keyword in select?
Answer:
ALL Keyword
The ALL keyword retains duplicate rows. It will display every row of the table without considering duplicate entries.
SELECT ALL Place FROM Student:
The above command will display all values of place field from every row of the table without considering the duplicate entries.

PART – III
III. Answer The Following Questions

Question 1.
Write note on SQL?
Answer:

1. The Structured Query Language (SQL) is a standard programming language to access and manipulate databases.
2. SQL allows the user to create, retrieve, alter, and transfer information among databases.
3. It is a language designed for managing and accessing data in a Relational Data Base Management System (RDBMS).

Question 2.
What are the various processing skills of SQL?
Answer:
The various processing skills of SQL are :
(i) Data Definition Language (DDL) :
The SQL DDL provides commands for defining relation schemes (structure), deleting relations, creating indexes and modifying relation schemes.

(ii) Data Manipulation Language (DML) :
The SQL DML includes commands to insert, delete, and modify tuples in the database.

(iii) Embedded Data Manipulation Language :
The embedded form of SQL is used in high level programming languages.

(iv) View Defintion :
The SQL also includes commands for defining views of tables.

(v) Authorization :
The SQL includes commands for access rights to relations and views of tables.

(vi) Integrity :
The SQL provides forms for integrity checking using condition.

(vii) Transaction control :
The SQL includes commands for file transactions and control over transaction processing.

Question 3.
How to create and work with database?
Answer:
Creating Database
(i) To create a database, type the following command in the prompt:
CREATE DATABASE database_name;
For example to create a database to store the tables:
CREATE DATABASE stud;

(ii) To work with the database, type the following command.
USE DATABASE;
For example to use the stud database created, give the command
USE stud;

Question 4.
What are the functions performed by DDL?
Answer:
A DDL performs the following functions :

1. It should identify the type of data division such as data item, segment, record and database file.
2. It gives a unique name to each data item type, record type, file type and data base.
3. It should specify the proper data type.
4. It should define the size of the data item.
5. It may define the range of values that a data item may use.
6. It may specify privacy locks for preventing unauthorized data entry.

Question 5.
Name the SQL Commands under TCL. Explain?
Answer:
SQL command which come under Transfer Control Language are:

Question 6.
Write about the parts of SQL Commands?
Answer:
Keywords They have a special meaning in SQL. They are understood as instructions.
Commands They are instructions given by the user to the database also known as statements.
Clauses They begin with a keyword and consist of keyword and argument.
Arguments They are the values given to make the clause complete.

Question 7.
Write note on delete command?
Answer:
DELETE COMMAND
The DELETE command permanently removes one or more records from the table. It removes the entire row, not individual fields of the row, so no field argument is needed. The DELETE command is used as follows :
DELETE FROM table-name WHERE condition;
For example to delete the record whose admission number is 104 the command is given as follows:
DELETE FROM Student WHERE Admno=104;

The following record is deleted from the Student table.
To delete all the rows of the table, the. command is used as :
DELETE * FROM Student;
The table will be empty now and could be destroyed using the DROP command.

Question 8.
Write note on delete, truncate, drop commands?
Answer:
DELETE, TRUNCATE AND DROP statement:
The DELETE command deletes only the rows from the table based on the condition given in the where clause or deletes all the rows from the table if no condition is specified. But it does not free the space containing the table.
The TRUNCATE command is used to delete all the rows, the structure remains in the table and free the space containing the table.
The DROP command is used to remove an object from the database. If you drop a table, all the rows in the table is deleted and the table structure is removed from the database. Once a table is dropped we cannot get it back.

Question 9.
Differentiate between and not between?
Answer:
BETWEEN and NOT BETWEEN Keywords
The BETWEEN keyword defies a range of values the record must fall into to make the condition true. The range may include an upper value and a lower value between which the criteria must fall into.
SELECT Admno, Name, Age, Gender FROM Student WHERE Age BETWEEN 18 AND 19;

The NOT BETWEEN is reverse of the BETWEEN operator where the records not satisfying the condition are displayed.
SELECT Admno, Name, Age FROM Student WHERE Age NOT BETWEEN 18 AND 19;

Question 10.
Differentiate IN and NOT IN
Answer:
IN Keyword
The IN keyword is used to specify a list of values which must be matched with the record values. In other words it is used to compare a column with more than one value. It is similar to an OR condition.
For example:
SELECT Admno, Name, Place FROM Student WHERE Place IN (“Chennai, “Delhi ”);

NOT IN: The NOT IN keyword displays only those records that do not match in the list. For example:
SELECT Admno, Name, Place FROM Student WHERE Place NOT IN (“Chennai”, ‘ “Delhi”);
will display students only from places other than “Chennai” and “Delhi”.

Question 11.
Write note on NULL?
Answer:
NULL Value:
The NULL value in a field can be searched in a table using the IS NULL in the WHERE c lause. For example to list all the students whose Age contains no value, the command is used as:
SELECT * FROM Student WHERE Age IS NULL.

Question 12.
Write note on Roll Back?
Answer:
ROLLBACK command
The ROLLBACK command restores the database to the last committed state. It is used with SAVEPOINT command to jump to a particular savepoint location. The syntax for the ROLLBACK command is :
ROLL BACK TO Save point name.

Question 13.
Write note on having clause?
Answer:
HAVING clause:
The HAVING clause can be used along with GROUP BY clause in the SELECT statement to place condition on groups and can include aggregate functions on them. For example to count the number of Male and Female students belonging to Chennai.
SELECT gender, COUNT(*) FROM Student GROUP BY Gender HAVING Place = ‘Chennai’;

The above output shows the number of Male and Female students in Chennai from the table student.

PART – IV
IV. Answer The Following Questions

Question 1.
Write about data type and description?
Answer:

Question 2.
Write about DML Commands?
Answer:
DML COMMANDS
Once the schema or structure of the table is created, values can be added to the table. The DML commands consist of inserting, deleting and updating rows into the table.

(i) INSERT command
The INSERT command helps to add new data to the database or add new records to the table. Syntax:
INSERT INTO <table-name> [column-list] VALUES (values);

(a) INSER T INTO Student (Admno, Name, Gender, Age, Place)
VALUES (100, ‘Ashish ’, ‘M\ 17, ‘Chennai);

(b) INSERT INTO Student (Admno, Name, Gender, Age, Place)
VALUES (10, ‘Adarsh’, ‘M’, 18, ‘Delhi);

(c) INSERT INTO Student VALUES (102, ‘Akshith \ ‘M’, ‘17, ’ ‘Bangalore);
The above command inserts the record into the student table.
To add data to only some columns in a record by specifying the column name and their data, it can be done by:

(d) INSERT INTO Student(Admno, Name, Place) VALUES (103, ‘Ayush’, ‘Delhi’);

(e) INSERT INTO Student (Admno, Name, Place) VALUES (104, ‘Abinandh ‘Chennai); The student table will have the following data:

(ii) DELETE COMMAND
The DELETE command permanently removes one or more records from the table. It removes the entire row, not individual fields of the row, so no field argument is needed. The DELETE command is used as follows:
DELETE FROM table-name WHERE condition;
For example to delete the record whose admission number is 104 the command is given as follows:
DELETE FROM Student WHERE Admno=104;

The following record is deleted from the Student table.
To delete all the rows of the table, the command is used as :
DELETE * FROM Student;
The table will be empty now and could be destroyed using the DROP command.

(iii) UPDATE COMMAND
The UPDATE command updates some or all data values in a database. It can update one or more records in a table. The UPDATE command specifies the rows to be changed using the WHERE clause and the new data using the SET keyword. The command is used as follows: UPDATE <table-name> SET column-name = value, column-name = value,… WHERE condition;
For example to update the following fields:
UPDATE Student SET Age = 20 WHERE Place = “Bangalore ”;
The above command will change the age to 20 for those students whose place is “Bangalore”.
The table will be as updated as below:

To update multiple fields, multiple field assignment can be specified with the SET clause separated by comma. For example to update multiple fields in the Student table, the command is given as:
UPDATE Student SETAge=18, Place = ‘Chennai’ WHERE Admno = 102;

The above command modifies the record in the following way.

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TN State Board 12th Chemistry Model Question Paper 2 English Medium

Instructions:

1. The question paper comprises of four parts
2. You are to attempt all the parts. An internal choice of questions is provided wherever: applicable
3. All questions of Part I, II, III, and IV are to be attempted separately
4. Question numbers 1 to 15 in Part I are Multiple choice Questions of one mark each.  These are to be answered by choosing the most suitable answer from the given four alternatives and writing the option code and the corresponding answer
5. Question numbers 16 to 24 in Part II are two-mark questions. These are lo be answered in about one or two sentences.
6. Question numbers 25 to 33 in Part III are three-mark questions. These are lo be answered in about three to five short sentences.
7. Question numbers 34 to 38 in Part IV are five-mark questions. These are lo be answered in detail. Draw diagrams wherever necessary.

Time: 3 Hours
Maximum Marks: 70

Part-I

Answer all the questions. Choose the correct answer. [15 × 1 = 15]

Question 1.
The following set of reactions are used in refining Zirconium

This method is known as ……………..
(a) Liquation
(b) Van Arkel process
(c) Zone refining
(d) Mond’s process
Answer:
(b) Van Arkel process

Question 2.
The stability of+1 oxidation state increases in the sequence ……………
(a) Al < Ga < In < Tl
(b) Tl < In < Ga < Al
(c) In < Tl < Ga < Al
(d) Ga < In < Al < Tl
Answer:
(a) A1 < Ga < In < Tl

Question 3.
Assertion : bond dissociation energy of fluorine is greater than chlorine gas.
Reason: chlorine has more electronic repulsion than fluorine.
(a) Both assertion and reason are true and reason is the correct explanation of assertion
(b) Both assertion and reason are true but reason is not the correct explanation of assertion
(c) Assertion is true but reason is false
(d) Both assertion and reason are false
Answer:
(d) Both assertion and reason are false

Question 4.
Which of the following pair has d¹⁰ electrons?
(a) Ti³⁺ , V⁴⁺
(b) CO³⁺ , Fe²⁺
(c) Cu⁺, Zn²⁺
(d) Mn²⁺, Fe³⁺
Answer:
(c) Cu⁺, Zn²⁺

Question 5.
Which is used for the separation of lanthanides, in softening of hard water and also in removing lead poisoning?
(a) [Ni(CO)₄]
(b) EDTA
(c) [Ni(DMG)₂]
(d) TiCl₄ + Al (C₂H₅ )₃
Answer:
(b) EDTA

Question 6.
The yellow colour in NaCl crystal is due to ……………..
(a) excitation of electrons in F centers
(b) reflection of light from CF ion on the surface
(c) refraction of light from Na+ ion
(d) all of the above
Answer:
(a) excitation of electrons in F centers

Question 7.
For a reaction Rate = k[acetone] then unit of rate constant and rate of reaction respectively is
(a) (mol L^-1 s^-1),(mol^-1/2 L^1/2 s^-1)
(b) (mol^-1/2 L^-1/2 s^-1) , (mol L^-1 s^-1)
(c) (mol^-1/2 L^-1/2 s^-1), (mol L^-1 s^-1)
(d) (mol L s^-1), (mol^-1/2 L^-1/2 s)
Answer:

In this case, rate = k [Acetone]^3/2
n= 3/2
mol^1-(3/2)L^(3/2)-1s^-1 ⇒ mol^-(1/2)L^(1/2)s^-1

Question 8.
Arrange the acids
(i) H₂SO₃
(ii) H₃PO₃ and
(iii) HClO₃ in the decreasing order of acidity.

(a) (i) > (iii) > (ii)
(b) (i) > (ii) > (iii)
(c) (ii) > (iii) > (i)
(d) (iii) > (i) > (ii)
Answer:
(d) (iii) > (i) > (ii)
Acidity is directly proportional to oxidation number. As the oxidation number of S, P and Cl in H₂SO₃, H₃PO₃ and HClO₃ is +4, +3, +5 respectively. So decreasing order of acidity will be (iii) > (i) > (ii)

Question 9.
The value of cell emf of Mercury button cell is –
(a) 1.35 V
(b) – 0.76 V
(c) 0.34 V
(d) 100 V
Answer:
(a) 1.35 V

Question 10.
In an electrical field, the particles of a colloidal system move towards cathode. The coagulation of the same sol is studied using K₂SO₄ (i), Na₃O₄ (ii), K₄[Fe(CN)₆] (iii) and NaCl (iv). Their coagulating power should be ……….
(a) II > I > IV > III
(b) III > II > I > IV
(c) I > II > III > IV
(d) none of these
Answer:
(b) III > II > I > IV

Question 11.
Which compound has the highest boiling point?
(a) Acetone
(b) Diethyl ether
(c) Methanol
(d) Ethanol
Answer:
(d) Ethanol

Question 12.
The reagent used to distinguish between acetaldehyde and benzaldehyde is
(a) Tollens reagent
(b) Fehling’s solution
(c) 2,4 – dinitrophenyl hydrazine
(d) semicarbazide
Answer:
(b) Fehling’s solution

Question 13.

(a) bromomethane
(b) a – bromo sodium acetate
(c) methanamine
(d) acetamide

Answer:
(c) methanamine

Question 14.
Match the following.

Answer:
(a) A – 3, B – 1, C – 4, D – 2

Question 15.
Regarding cross-linked or network polymers, which of the following statement is incorrect?
(a) Examples are Bakelite and melamine
(b) They are formed from bi and tri-functional monomers
(c) They contain covalent bonds between various linear polymer chains
(d) They contain strong covalent bonds in their polymer chain
Answer:
(d) They contain strong covalent bonds in their polymer chain

Part – II

Answer any six questions. Question No. 21 is compulsory. [6 × 2 = 12]

Question 16.
Give the uses of zinc.
Answer:

• Metallic zinc is used in galvanising metals such as iron and steel structures to protect them . from rusting and corrosion.
• Zinc is also used to produce die-castings in the automobile, electrical and hardware industries.
• Zinc oxide is used in the manufacture of many products such as paints, rubber, cosmetics, pharmaceuticals, plastics, inks, batteries, textiles and electrical equipment. Zinc sulphide is used in making luminous paints, fluorescent lights and x-ray screens.
• Brass an alloy of zinc is used in water valves and communication equipment as it is highly resistant to corrosion.

Question 17.
Explain why fluorine always exhibit an oxidation state of-1?
Answer:
Fluorine the most electronegative element than other halogens and cannot exhibit any positive oxidation state. Fluorine does not have d-orbital while other halogens have d-orbitals. Therefore fluorine always exhibit an oxidation state of-1 and others in halogen family shows +1, +3, +5 and +7 oxidation states.

Question 18.
What is Zeigler -Natta catalyst? In which reaction it is used? Give equation.
Answer:
A mixture of TiCl₄ and trialkyl aluminium is Zeigler – Natta catalyst. It is used in the polymerization.

Question 19.
Give any three characteristics of ionic crystals.
Answer:

• Ionic solids have high melting points.
• These solids do not conduct electricity, because the ions are fixed in their lattice positions. ‘
• They do conduct electricity in molten state (or) when dissolved in water because, the ions are free to move in the molten state or solution.

Question 20.
How is surface area of the reactant affect the rate of the reaction?
Answer:

• In heterogeneous reactions, the surface area of the solid reactants play an important role in deciding the rate.
• For a given mass of a reactant, when the particle size decreases surface area increases. Increase in surface area of reactant leads to more collisions per litre per second and hence the rate of reaction is increased.
• For example, powdered calcium carbonate reacts much faster with dilute HCl than with the same mass of CaCO₃ as marble.

Question 21.
K_sp of Al(OH)₃ is 1 x 10^-15M. At whatpH does 1.0 × 10^-3 3M Al³⁺ precipitate on the addition of buffer of NH₄Cl and NH₄OH solution?
Answer:
Al(OH)₃ ⇌ Al³⁺ (aq) + 3OH^– (aq)
K_sp – [Al³⁺ ][OH^–]³
Al(OH)₃ precipitates when
[Al³⁺ ] [OH^– ]³ > K_sp
(1 × 10^-3 )[OH^– ]³ > 1 × 10^-15
[OH^–]^-3] > 1 × 10^-12
[OH^– ] > 1 × 10^-4 M
[OH^– ] = 1 × 10^-4 M
pOH = – log_1o[OH^–] = – log(1 × 10^-4) = 4
pH = 14 – 4 = 10
Thus, Al(OH)₃ precipitates at a pH of 10

Question 22.
Arrange the following in the increasing order of their boiling point and give a reason for your ordering: Butan – 2- ol, Butan -l-ol, 2 -methylpropan -2-ol
Answer:
Boiling points increases regularly as the molecular mass increases due to a corresponding increase in their Van der waal’s force of attraction. Among isomeric alcohols 2°-alcohols have lower boiling points than 1 “-alcohols due to a corresponding decreases in the extent of H-bonding because of steric hindrance. Thus the boiling point of Butan – 2- ol is lower than that of Butan – l-ol. Overall increasing order of boiling points is,
2-methylpropan-2-ol < Butan-2- ol < Butan – l-ol

Question 23.
What are the uses of Benzaldehyde?
Answer:

• as a flavoring agent
• in perfumes
• in dye intermediates
• as starting material for the synthesis of several other organic compounds like cinnamaldehyde, cinnamic acid, benzoyl chloride etc.

Question 24.
What are anti fertility drugs? Give examples.
Answer:
Artificially drugs are chemical substances which suppress the action of hormones that promote pregnancy. These drugs actually reduce the chances of pregnancy and act as a protection. Antifertility drugs are made up of derivatives of synthetic progesterone or a combination of derivatives of oestrogen and progesterone.
Example : Ethynylestradiol, menstranol and norethynodrel etc.

Part – III

Answer any six questions. Question No. 30 is compulsory. [6 ×3 = 18]

Question 25.
Give the uses of silicones.
Answer:
Uses of silicones:

• Silicones are used for low temperature lubrication and in vacuum pumps, high temperature oil baths etc.
• They are used for making water proofing clothes
• They are used as insulting material in electrical motor and other appliances
• They are mixed with paints and enamels to make them resistant towards high temperature, sunlight, dampness and chemicals.

Question 26.
Complete the following reactions.
1. NaCl + MnO₂ + H₂SO₄ →
2. I₂ + S₂O₃^2-
3. P₄ + NaOH + H₂O →
Answer:
1. 4NaCl + MnO₂ + 4H₂SO₄ → Cl₂ + MnCl₂ + 4NaHSO₄ + 2H₂O
2. I₂ + 2S₂O₃^2- → S₄O₆^2- + 2I^–
3. P₄ + 3NaOH + 3H₂O → 3NaH₂PO₂ + PH₃↑

Question 27.
Draw and explain about the structure of chromate and dichromate ion,

Answer:

• Both chromate and dichromate ions are oxo anions of chromium and they are moderately strong oxidising agents.
• In both structures, chromium is in +6 oxidation state.
• In an aqueous solution, chromate and dichromate ions can be inter convertible, and in an alkaline solution, chromate ion is predominant, whereas dichromate ion becomes predominant in acidic solutions.

Question 28.
Why ionic crystals are hard and brittle?
Answer:
The ionic compounds are very hard and brittle. In ionic compounds the ions are rigidly held in a lattice because the positive and negative ions are strongly attracted to each other and difficult to separate. But the brittleness of a compound is now easy to shift the position of atoms or ions in a lattice. If we apply a pressure on the ionic compounds the layers shifts slightly. The same charged ions in the lattice comes closer. A repulsive forces arises between same charged ions, due to this repulsions the lattice structure breaks down chemical bonding.

Question 29.
Paracetamol is prescribed to take once in 6 hours. Justify this statement.
Answer:

• Paracetamol is a well known antipyretic and analgesic that is prescribed in cases of fever
  and body pain.
• Paracetamol has a half life of 2.5 hours within the body, (i.e) the plasma concentration of the drug is halved after 2.5 hours. So after 10 hours (4 half lives), only 6.25% of drug remains. Based on this, the dosage and frequency will be decided.
• In the case of paracetamol, it is usually prescribed to take once in 6 hours.

Question 30.
A solution of a salt of metal was electrolysed for 150 minutes with a current of 0. 15 amperes. The mass of the metal deposited at the cathode is 0.783g. Calculate the equivalent mass of the metal.
Answer:
Given, I = 0.15 amperes
t = 150 mins ⇒ t = 150 x 60 sec ⇒ t = 9000 sec
Q = It ⇒ Q = 0.15 x 9000 coulombs ⇒ Q = 1350 coulombs Hence, 135 coulombs of electricity deposit is equal to \(\frac{0.783 \times 96500}{1350}=55.97\) g of metal.
∴ Hence equivalent mass of the metal is 55.97

Question 31.
What happens when
i. 2 – Nitropropane boiled with HCl
ii. Nitrobenzen electrolytic reduction in strongly acidic medium.
Answer:
i. 2 – Nitropropane boiled with HCl: 2-nitropropane upon hydrolysis with boiling HCl give a ketone (2-propanone) and nitrous oxide.

ii. Nitrobenezen electrolytic reduction in strongly acidic medium: Electrolytic reduction of nitrobenzene in weakly acidic medium gives aniline but in strongly acidic medium, it gives p-aminophenol obviously through the acid – catalysed rearrangement of the initially formed phenylhydroxylamine.

Question 32.
Write a short note on peptide bond.
Answer:

• The amino acids are linked covalently by peptide bonds.
• The carbonyl group of the first amino acid react with the amino group of the second amino acid to give an amide linkage (-CONH) between these aminoacids. This amide linkage is called peptide bond.

• The resulting compound is called a dipeptide. Because, two amino acids are inovlved for getting one peptide bond.
• If large number of amino acids combined through peptide bond, the resulting giant molecule is called a protein.
• The amino end of the peptide is known as N-terminal, while the carboxy end is called C – terminal.

Question 33.
(i) What class of drug is Ranitidine?
(ii) If water contains dissolved Ca ions, out of soaps and synthetic detergents, which will you use for cleaning clothes?
(iii) Which of the following is an antisepctic? 0.2% phenol, 1% phenol.
Answer:
(i) It is an antacid.
(ii) In this case we use synthetic detergents because it give foam with hard water.
(iii) 0.2% solution of phenol acts as antiseptic.

Part – IV

Answer all the questions. [5 × 5 = 25]

Question 34.
(a) (0 Explain the concentration of copper pyrites and galena ores. (3)
(ii) Out of LU(OH)₃ and La(OH)₃ which is more basic and why? (2)
(b) Explain the preparation of silicones. (5)
Answer:
(a) (i) Froth floatation: This method is commonly used to concentrate sulphide ores such as galena (PbS), zinc blende (ZnS) etc. In this method, the metallic ore particles which are preferentially wetted by oil can be separated from gangue.

In this method, the crushed ore is suspended in water and mixed with frothing agent such as pine oil, eucalyptus oil etc. A small quantity of sodium ethyl xanthate which acts as a collector is also added. A froth is generated by blowing air through this mixture.

The collector molecules attach to the ore particle and make them water repellent. As a result, ore particles, wetted by the oil, rise to the surface along with the froth. The froth is skimmed off and dried to recover the concentrated ore. The gangue particles that are preferentially wetted by water settle at the bottom.

When a sulphide ore of a metal of interest contains other metal sulphides as impurities, depressing agents such as sodium cyanide, sodium carbonate etc are used to selectively prevent other metal sulphides from coming to the froth. For example, when impurities such as ZnS is present in galena (PbS), sodium cyanide (NaCN) is added to depresses the floatation property of ZnS by forming a layer of zinc complex Na₂[Zn(CN)₄] on the surface of zinc sulphide.

(ii) 1. As we move from Ce³⁺ to Lu³⁺, the basic character of Lu³⁺ ions decreases.
2. Due to the decrease in the size of Lu³⁺ ions, the ionic character of Lu – OH bond decreases, covalent character increases which results in the decrease in the basicity.
3. Hence, La(OH)₃ is more basic than Lu(OH)₃.

[OR]

(b) Generally silicones are prepared by the hydrolysis of dialkyldichlorosilanes (R₂SiCl₂ ) or diaryldichlorosilanes Ar₂SiCl₂, which are prepared by passing vapours of RCl or ArCl over silicon at 570 K with copper as a catalyst.

The hydrolysis of dialkylchloro silanes R₂SiCl₂ yields to a straight chain polymer which grown from both the sides

The hydrolysis of monoalkylchloro silanes RSiCl₃ yields to a very complex cross linked polymer. Linear silicones can be converted into cyclic or ring silicones when water molecules is removed from the terminal -OH groups.

Question 35.
(a) Bleaching action of chlorine is permanent – Justify this statement and also give the uses of chlorine. (5)
[OR]
(b) (i) Complete the following (3)


(ii) What is linkage isomerism? Explain with an example.
Answer:
(a) Chlorine is a strong oxidising and bleaching agent because of the nascent oxygen.
H₂O + Cl₂ → HCl + HOCl (Hypo chlorous acid)
HOCl → HCl + (O)

Colouring matter + Nascent oxygen → Colourless oxidation product
Therefore, bleaching of chlorine is permanent. It oxidises ferrous salts to ferric, sulphites to sulphates and hydrogen sulphide to sulphur.

Uses of chlorine:

• Purification of drinking water
• Bleaching of cotton textiles, paper and rayon
• It is used in extraction of gold and platinum

[OR]

(b) (i)

(ii) This type of isomers arises when an ambidentate ligand is bonded to the central metal atom/ion through either of its two different donor atoms.
For examples,
[CO(NH₃)₅ONO]Cl₂
(Pentaammine nitrito cobalt (III) chloride)
O – attached. (Red in colour).
[CO(NH₃)₅NO₂]Cl₂
(Pentaammine nitro cobalt (III) chloride)
N – attached (Yellow-brown in colour).

Question 36.
(a) (i) What is the two dimensional coordination number of a molecule in square close packed layer? (2)
(ii) Derive the integrated rate law for a first order reaction? (3)
[OR]
(b) (i) Define solubility product. (2)
(ii) What is the pH of an aqueous solution obtained by mixing 6 gram of acetic acid and 8.2 gram of sodium acetate and making the volume equal to 500 ml. (Given: Ka for acetic acid is 1.8 × 10^-5) (3)
Answer:
(a) (i) Square close packing : When the spheres of the second ” row are placed exactly above those of the first row.
This way the spheres are aligned horizontally as well as vertically. The arrangement is AAA type. Coordination number is 4.
(ii) Areaction whose rate depends on the reactant concentration raised to the first power is called a first order reaction.
First order reaction is A → product

Rate law can be expressed as, Rate = k [A]1
Where, k is the first order rate constant

Integrate the above equation (1) between the limits of time t = O and time equal to t,
while the concentration varies from initial concentration [A₀]to [A] at the later time.

This equation (2) is in natural logarithm. To convert it into usual logarithm with base 10,
we have to multiply the term by 2.303

[OR]

(b) (i) Solubility product : It is defined as the product of the molar concentration of the constituent ions, each raised to the power of its stoichiometric co-efficient in a balanced equilibrium equation.

(ii) According to Henderson — Hessalbalch equation,

Question 37.
(a) (i) Why for CH₃COOH cannot be determined experimentally? (2)
(ii) Write about the classification of organic nitro compounds. (3)
[OR]
(b) Describe about condensation methods of preparation of colloids. (OR)
Describe chemical methods of preparation of colloids. (5)
Answer:
(a) (i) Molar conductivity of weak electrolytes keeps on increasing with dilution and does not
become constant even at very large dilution.

(ii)

[OR]

(b) When the substance for colloidal particle is present as small sized particle, molecule or ion, they are brought to the colloidal dimension by condensation methods.
i. Oxidation method:- When hydroiodic acid is treated with iodic acid I sol is obtained.
HIO₃ +5HI → 3H₂O + 3I _2(sol)

ii. Reduction method:- Gold sol is prepared by reduction of auric chloride using formaldehyde.
2 AuCl₃ + 3 HCHO + 3 H₂O (sol) → 2 Au_(sol) + 6HCl + 3HCOOH

iii. Hydrolysis:- Ferric chloride is hydrolysed to get ferric hydroxide colloid
FeCl₃ + 3H₂O → Fe(OH)₃ (sol) + 3HCl

iv. Double decomposition:- When hydrogen sulphide gas is passed through a solution of arsenic oxide, a yellow coloured arsenic sulphide is obtained as a colloidal solution.
As₂O₃ + 3H₂ → As ₂S₃ + 3H₂O

v. Decomposition:- When few drops of an acid is added to a dilute solution of sodium thiosulphate, sulphur colloid is produced by the decomposition of sodium thio sulphate.
S₂O₃^2- + 2H⁺ → S_(sol) + H₂O + SO₂

Question 38.
(a) (i) What is Clemmensen reduction ? Explain it. (2)
(ii) Write the structure of the major product of the aldol condensation of benzaldehyde
with acetone. (3)
[OR]
(b) (i)How will you convert nitrobenzene into (2)
1. 1,3, 5 – trinitrobenzene 2. o añd p- nitrophenol
(ii) Differentiate between Globular and fibrous proteins. (3)
Answer:
(a) (i) Aldehyde and ketones when heated with zinc amalgam and concentrated hydrochloric acid give hydrocarbons. This reaction is known as Clemmensen reduction.

(ii) Aldol condensation of benzaldehyde with acetone:

(b) (i) 1. Conversion of nitrobenzene into 1,3,5 – trinitrobenzene:

2. Conversion of nitrobenzene into o and p- nitrophenol:
Nitrobenzene heated with solid KOH at 340 K gives a low yield of a mixture of O-and P-nitrophenols.

(ii) Difference between Globular and fibrous proteins.

Students can Download Tamil Nadu 12th Physics Model Question Paper 1 English Medium Pdf, Tamil Nadu 12th Physics Model Question Papers helps you to revise the complete Tamilnadu State Board New Syllabus and score more marks in your examinations.

TN State Board 12th Physics Model Question Paper 1 English Medium

Instructions:

1. The question paper comprises of four parts
2. You are to attempt all the parts. An internal choice of questions is provided wherever: applicable
3. All questions of Part I, II, III and IV are to be attempted separately
4. Question numbers 1 to 15 in Part I are Multiple choice Questions of one mark each. These are to be answered by choosing the most suitable answer from the given four alternatives and writing the option code and the corresponding answer
5. Question numbers 16 to 24 in Part II are two-mark questions. These are lo be answered in about one or two sentences.
6. Question numbers 25 to 33 in Part III are three-mark questions. These are lo be answered in about three to five short sentences.
7. Question numbers 34 to 38 in Part IV are five-mark questions. These are lo be answered in detail. Draw diagrams wherever necessary.

Time: 3 Hours
Max Marks: 70

PART – 1

Answer all the questions. Choose the correct answer. [15 × 1 = 15]

Question 1.
An electric dipole is placed at an alignment angle of 30° with an electric field of 2 × 10⁵ NC^-1. It experiences a torque equal to 8 N m. The charge on the dipole if the dipole length is 1 cm is ……………….
(a) 4 mC
(b) 8 mC
(c) 5 mC
(d) 7 mC
Answer:
(b) 8 mC

Question 2.
Dielectric constant of metals is
(a) 1
(b) greater then 1
(c) zero
(d) infinite
Answer:
(d) infinite

Question 3.
Two wires of A and B with circular cross section made up of the same material with equal lengths. Suppose R_A = 3 R_B, then what is the ratio of radius of wire A to that of B?
(a) 3
(b) √3
(c) \(\frac{1}{\sqrt{3}}\)
(d) \(\frac{1}{3}\)
Answer:
(c) \(\frac{1}{\sqrt{3}}\)

Question 4.
A circular coil of radius 5 cm and 50 turns carries a current of 3 ampere. The magnetic dipole moment of the coil is
(a) 1.0 amp – m²
(b) 1.2 amp – m²
(c) 0.5 amp – m²
(d) 0.8 amp – m²
Answer:
(b) 1.2 amp – m²

Question 5.
A straight conductor carrying a current I, is split into a circular loop of radius r as shown in the figure. The magnetic field at the centre O of the circle, in tesla is …………..

(a) \(\frac{\propto_{0} \mathrm{I}}{2 r}\)
(b) \(\frac{\mu_{0} I}{2 \pi r}\)
(c) \(\frac{\mu_{0} I}{\pi r}\)
(d) zero
Hint Field due to the upper and lower semicircles will cancel out.
Answer:
(d) zero

Question 6.
The flux linked with a coil at any instant t is given by Φ_B = 10t² – 50t + 250. The induced emf at t = 3s is ………………. .
(a) -190 V
(b) -10 V
(c) 10 V
(d) 190 V
Answer:
(b) -10 V

Question 7.
Quantity that remains unchanged in a transformer is
(a) voltage
(b) current
(c) frequency
(d) none of these
Answer:
(c) frequency

Question 8.
The electric and the magnetic field, associated with an electromagnetic wave, propagating along X axis can be represented by
(a) \(\overrightarrow{\mathrm{E}}\) = E₀ĵ and \(\overrightarrow{\mathrm{B}}\) = B₀K̂
(b) \(\overrightarrow{\mathrm{E}}\) = E₀K̂ and \(\overrightarrow{\mathrm{B}}\) = B₀ĵ
(c) \(\overrightarrow{\mathrm{E}}\) = E₀î and \(\overrightarrow{\mathrm{B}}\) = B₀ĵ
(d) \(\overrightarrow{\mathrm{E}}\) = E₀ĵ and \(\overrightarrow{\mathrm{B}}\) = B₀ĵ
Answer:
(b) \(\overrightarrow{\mathrm{E}}\) = E₀K̂ and \(\overrightarrow{\mathrm{B}}\) = B₀ĵ

Question 9.
A ray of light strikes a glass plate at an angle 60°. If the reflected and refracted rays are perpendicular to each other, the refractive index of the glass is
(a) √3
(b) \(\frac{3}{2}\)
(c) \(\sqrt{\frac{3}{2}}\)
(d) 2
Hint. Angle of refraction r = 60° ;
Angle of incident i = 30°
sin i = n × sin r
n = \(\frac{\sin 30^{\circ}}{\sin 60^{\circ}}\) = √3
Answer:
(a) √3

Question 10.
For light incident from air onto a slab of refractive index 2. Maximum possible angle of refraction is
(a) 30°
(b) 45°
(c) 60°
(d) 90°
Hint. From Snell’s law, µ = \(\frac{\sin i}{\sin r}\)
Now consider an angle of incident is 90°
sinr = \(\frac{\sin 90^{\circ}}{2}\)
r = sin^-1 (0.5)
r = 30°
Answer:
(a) 30°

Question 11.
A light of wavelength 500 nm is incident on a sensitive plate of photoelectric work function 1.235 eV. The kinetic energy of the photo electrons emitted is be (Take h = 6.6 × 10^-34 Js)
(a) 0.58 eV
(b) 2.48 eV
(c) 1.24 eV
(d) 1.16 eV
Hint.

= (2.48 – 1.235) eV= 1.245 eV
Answer:
(c) 1.24 eV

Question 12.
In a hydrogen atom, the electron revolving in the fourth orbit, has angular momentum equal to ………….. .
(a) h
(b) \(\frac{h}{\pi}\)
(c) \(\frac{4 h}{\pi}\)
(d) \(\frac{2 h}{\pi}\)
Hint Angular momentum of an electron is an integral multiple of \(\frac{h}{2 \pi}\)
According to Bohr atom model,
Angular momentum of an electron mvr = \(\frac{nh}{2 \pi}\)
n = 4th orbit = \(\frac{4h}{2 \pi}\)
mvr = \(\frac{2 h}{\pi}\)
Answer:
(d) \(\frac{2 h}{\pi}\)

Question 13.
The barrier potential of a silicon diode is approximately
(a) 0.7 V
(b) 0.3V
(c) 2.0 V
(d) 2.2V
Answer:
(a) 0.7 V

Question 14.
The signal is affected by noise in a communication system
(a) At the transmitter
(b) At the modulator
(c) In the channel
(d) At the receiver
Answer:
(c) In the channel

Question 15.
The particle which gives mass to protons and neutrons are
(a) Higgs particle
(b) Einstein particle
(c) Nanoparticle
(d) Bulk particle
Answer:
(a) Higgs particle

PART – II

Answer any six questions. Question No. 21 is compulsory. [6 × 2 = 12]

Question 16.
Define ‘electrostatic potential”.
Answer:
The electric potential at a point P is equal to the work done by an external force to bring a unit positive charge with constant velocity from infinity to the point P in the region of the external electric field \(\overrightarrow{\mathrm{E}} \cdot\)

Question 17.
Define temperature coefficient of resistance.
Answer:
It is defined as the ratio of increase in resistivity per degree rise in temperature to its resistivity at T₀
∴ \(\alpha=\frac{\rho_{\mathrm{T}}-\rho_{\mathrm{o}}}{\rho_{\mathrm{o}}\left(\mathrm{T}-\mathrm{T}_{\mathrm{o}}\right)}=\frac{\Delta \rho}{\rho_{\mathrm{o}} \Delta \mathrm{T}}\)

Question 18.
The self-inductance of an air-core solenoid is 4.8 mH. If its core is replaced by iron core, then its self-inductance becomes 1.8 H. Find out the relative permeability of iron.
Answer:
L_air = 4.8 × 10^-3
L_iron = 1.8 H
L_air = μ₀n²Al = 4.8 × 10″3H
L_iron = μn²Al = μ₀μ_r n²Al= 1.8 H
∴ \(\mu_{r}=\frac{L_{\text {ipon }}}{L_{\text {air }}}=\frac{1.8}{4.8 \times 10^{-3}}=375\)

Question 19.
What is meant by Fraunhofer lines?
Answer:
When the spectrum obtained from the Sun is examined, it consists of large number of dark lines (line absorption spectrum). These dark lines in the solar spectrum are known as Fraunhofer lines.

Question 20.
What is power of a lens?
Answer:
The power of a lens P is defined as the reciprocal of its focal length. P = \(\frac{1}{f}\)
The unit of power is diopter D.

Question 21.
Calculate the cut-off wavelength and cutoff frequency of x-rays from an x-ray tube of accelerating potential 20,000 V.
Answer:
The cut-off wavelength of the characteristic x-rays is

Question 22.
What is mass defect?
Answer:
The mass of any nucleus is always less than the sum of the mass of its individual constituents. The difference in mass Am is called mass defect.
Δm = (Zm_p + Nm_n) – M

Question 23.
Simplify the Boolean identity AC + ABC = AC
Answer:
Step 1: AC (1 + B) = AC.1 [OR law-2]
Step 2: AC . 1 = AC [AND law 2]
Therefore, AC + ABC = AC
Circuit Description
Thus the given statement is proved.

Question 24.
What do you mean by Internet of Things?
Answer:
Internet of Things (IoT), it is made possible to control various devices from a single device. Example: home automation using a mobile phone.

PART-III

Answer any six questions. Question No. 26 is compulsory. [6 × 3 = 18]

Question 25.
Give the relation between electric field and electric potential.
Answer:
Consider a positive charge q kept fixed at the origin. To move a unit positive charge by a small ‘ distance dx in the electric field E, the work done is given by dW = -E dx. The minus sign implies that work is done against the electric field. This work done is equal to electric potential difference. Therefore,
dW = dV. (or) dV = -E dx
Hence E = \(-\frac{d V}{d x}\)
The electric field is the negative gradient of the electric potential.

Question 26.
A cicopper wire of 10”6 m2 area of cross section, carries a current of 2 A. If the number of electrons per cubic meter is 8 × 10²⁸, calculate the current density and average drift velocity
Answer:
Cross-sections area of copper wire, A = 10^-6 m²
I = 2A
Number of electron, n = 8 × 10²⁸
Current density, J = \(\frac{I}{A}=\frac{2}{10^{-6}}\)
J = 2 × 10⁶Am^-2
Average drift velocity, V_d = \(\frac{I}{n e A}\)
e is the charge of electron = 1.6 × 10^-9 C

V_d = 0.15625 × 10^-3 ; V_d = 15.6 × 10^-5 ms^-1

Question 27.
compare dia, para and ferromagnetism.
Answer:

Question 28.
State Faraday’s laws of electromagnetic induction.
Answer:
First law: Whenever magnetic flux linked with a closed circuit changes, an emf is induced in the circuit.
Second law: The magnitude of induced emf in a closed circuit is equal to the time rate of change of magnetic flux linked with the circuit.

Question 29.
Why does sky appear blue?
Answer:
Blue colour of the sky is due to scattering of sunlight by air molecules. According to Rayleigh’s law, intensity of scattered light, I ∝ \(\frac{1}{\lambda^{4}}\). So blue light of shorter wavelength is scattered much more than red light of larger wavelength. The blue component is proportionally more in light coming from different parts of the sky. That is why the sky appears blue.

Question 30.
Write down the postulates of Bohr atom model.
Answer:
Postulates of Bohr atom model:
The electron in an atom moves around nucleus in circular orbits under the influence of Coulomb electrostatic force of attraction. This Coulomb force gives necessary centripetal force for the electron to undergo circular motion.

Electrons in an atom revolve around the nucleus only in certain discrete orbits called stationary orbits where it does not radiate electromagnetic energy. Only those discrete orbits allowed are stable orbits.

Question 31.
State De Morgan’s first and second theorems.
Answer:
De Morgan’s First Theorem:
The first theorem states that the complement of the sum of two logical inputs is equal to the product of its complements.
\(\overline{\mathrm{A}+\mathrm{B}}=\overline{\mathrm{A}} \cdot \overline{\mathrm{B}}\)

De Morgan’s Second Theorem:
The second theorem states that the complement of the product of two inputs is equal to the sum of its complements.
\(\overline{\mathrm{A} \cdot \mathrm{B}}=\overline{\mathrm{A}}+\overline{\mathrm{B}}\)

Question 32.
Write down the advantages and limitations of amplitude modulation (AM).
Answer:
Advantages of AM

• Easy transmission and reception
• Lesser bandwidth requirements
• Low cost

Limitations of AM

• Noise level is high
• Low efficiency
• Small operating range

Question 33.
What are black holes?
Answer:
Black holes are end stage of stars which are highly dense massive object. Its mass ranges from 20 times mass of the sun to 1 million times mass of the sun. It has very strong gravitational force such that no particle or even light can escape from it. The existence of black holes is studied when the stars orbiting the black hole behave differently from the other starts. Every galaxy has black hole at its center. Sagittarius A* is the black hole at the center of the Milky Way galaxy.

PART – IV

Answer all the questions. [5 × 5 = 25]

Question 34.
(a) Derive an expression for the torque experienced by a dipole due to a uniform electric field.
Answer:

Torque experienced by an electric dipole in the uniform electric field: Consider an electric dipole of dipole moment \(\overrightarrow{\mathrm{P}}\) placed in a uniform electric field \(\overrightarrow{\mathrm{E}}\) whose field lines are equally spaced and point in the same direction. The charge +q will experience a force q \(\overrightarrow{\mathrm{E}}\) in the direction of the field and charge -q will experience a force -q \(\overrightarrow{\mathrm{E}}\) in a direction opposite to the field. Since the external field
\(\overrightarrow{\mathrm{E}}\) is uniform, the total force acting on the dipole is zero. These two forces acting at different points will constitute a couple and the dipole experience a torque. This torque tends to rotate the dipole. (Note that electric field lines of a uniform field are equally spaced and point in the same direction). The total torque on the dipole about the point O
\(\vec{\tau}=\overrightarrow{O A} \times(-q \vec{E})+\overrightarrow{O B} \times q \vec{E}\)
Using right-hand corkscrew rule, it is found that total torque is perpendicular to the plane of the paper and is directed into it.
The magnitude of the total torque
\(\vec{\tau}=|\overrightarrow{\mathrm{OA}}|(-q \overrightarrow{\mathrm{E}}) \sin \theta+|\overrightarrow{\mathrm{OB}} \| q \overrightarrow{\mathrm{E}}| \sin \theta\)
\(\vec{\tau}\) = qE 2a sin θ
where θ is the angle made by \(\vec{p}\) with \(\vec{E}\). Since p = 2aq, the torque is written in terms of the vector product as
\(\vec{\tau}=\vec{p} \times \vec{E}\)
The magnitude of this torque is \(\tau\) =pE sin θ and is maximum when θ = 90°.
This torque tends to rotate the dipole and align it with the electric field \(\vec{E}\) . Once \(\vec{p}\) is aligned with \(\vec{E}\), the total torque on the dipole becomes zero.

OR

Question 34.
(b) Explain the determination of the internal resistance of a cell using voltmeter.
Answer:

Determination of internal resistance : The emf of cell \(\xi\) is measured by connecting a high resistance voltmeter across it without connecting the external resistance R. Since the voltmeter draws very little current for deflection, the circuit may be considered as open. Hence, the voltmeter reading gives the emf of the cell. Then, external resistance R is included in the circuit and current I is established in the circuit. The potential difference across R is equal to the potential difference across the cell (V).
The potential drop across the resistor R is
V = IR …………. (1)
Due to internal resistance r of the cell, the voltmeter reads a value V, which is less than the emf of cell . It is because, certain amount of voltage (Ir) has dropped across the internal resistance r.
Then V = \(\xi\) – Ir
Ir = \(\xi\) – V
Dividing equation (2) by equation (1). we get
\(\begin{aligned}
\frac{I r}{I R} &=\frac{\xi-V}{V} \\
r &=\left|\frac{\xi-V}{V}\right| R
\end{aligned}\)
Since \(\xi\), V and R are known, internal resistance r can be determined.

Question 35.
(a) Obtain the magnetic induction at a point on the equatorial line of a bar magnet.
Answer:
Magnetic field at a point along the equatorial line due to a magnetic dipole (bar magnet) Consider a bar magnet NS. Let N be the north pole and S be the south pole of the bar magnet, each with pole strength q_m and separated by a distance of 2l. The magnetic field at a point C (lies along the equatorial line) at a distance r from the geometrical center O of the bar magnet can be computed by keeping unit north pole (q_m C = 1 A m) at C. The force experienced by the unit north pole at C due to pole strength N – S can be computed using Coulomb’s law of
magnetism as follows:

The force of repulsion between North Pole of the bar magnet and unit north pole at point C
(in free space) is
\(\overrightarrow{\mathrm{F}}_{\mathrm{N}}=-\mathrm{F}_{\mathrm{N}} \cos \theta \hat{i}+\mathrm{F}_{\mathrm{N}} \sin \theta \hat{j}\) ……….. (2)
Where F_N = \(\frac{\mu_{0}}{4 \pi} \frac{q_{m}}{r^{\prime 2}}\)

From equation (1) and equation (2). the net force at point C is \(\overrightarrow{\mathrm{F}}=\overrightarrow{\mathrm{F}}_{\mathrm{N}}+\mathrm{F}_{\mathrm{S}}\) This net force is equal to the magnetic field at the point C.
\(\overrightarrow{\mathrm{B}}\) =—(FN+Fs)cosOi
Since, F_N = F_s

In a right angle triangle NOC as shown in the Figure 1

Substituting equation 4 in equation 3 we get


Since, magnitude of magnetic dipole moment is |\(\vec{p}\)_m| = P_m = q_m.2l and substituting in equation (5), the magnetic field at a point C

If the distance between two poles in a bar magnet are small (looks like short magnet) when compared to the distance between geometrical center O of bar magnet and the location of point
C i.e., r >>l, then,
(r² + l²)^3/2 ≈ r³ …….. (7)
Therefore, using equation (7) in equation (6), we get

Since P_mî = \(\vec{p}\) _m in general, the magnetic field al equatorial point is given by

Note that magnitude of B_axial is twice that of magnitude of B_equatorial and the direction of B_axial and B_equatorial are opposite.

[OR]

Question 35.
(b) How will you induce an emf by changing the area enclosed by the coil?
Answer:
Induction of emf by changing the area of the coil: Consider a conducting rod of length 1 moving with a velocity v towards left on a rectangular metallic framework. The whole arrangement is placed in a uniform magnetic field B whose magnetic lines are perpendicularly directed into the plane of the paper. As the rod moves from AB to DC in a time dt , the area enclosed by the loop and hence the magnetic flux through the loop decreases.

The change in magnetic flux in time dr is
dΦ_B = B × change in area
= B × AreaABCD
= Blvdt
since Area ABCD l(vdt)
or = \(\frac{d \Phi_{\mathrm{B}}}{d t}=\mathrm{B} l v\)
As a result of change in flux, an emf is generated in the loop. The magnitude of the induced emf is
\(\varepsilon=\frac{d \Phi_{\mathrm{B}}}{d t}=\mathrm{B} / v\)
This emf is called motional emf. The direction of induced current is found to be clockwise from Fleming’s right hand rule.

Question 36.
(a) Write down Maxwell equations in integral form.
Answer:
Maxwell’s equations in integral form: Electrodynamics can be summarized into four basic equations, known as Maxwell’s equations. These equations are analogous to Newton’s equations in mechanics. Maxwell’s equations completely explain the behaviour of charges, currents and prop

1. First equation is nothing but the Gauss’s law. It relates the net electric flux to net electric charge enclosed in a surface. Mathematically, it is expressed as
\(\oint \overrightarrow{\mathrm{E}} \cdot d \overrightarrow{\mathrm{A}}=\frac{\mathrm{Q}_{\text {enclosed }}}{\varepsilon_{0}}\)
Where \(\overrightarrow{\mathrm{E}}\) is the electric field and Q_enclosed is the charge enclosed. This equation is true for both discrete or continuous distribution of charges. It also indicates that the electric field lines start from positive charge and terminate at negative charge. This implies that the electric field lines do not form a continuous closed path. In other words, it means that isolated positive charge or negative charge can exist.

2. Second equation has no name. But this law is similar to Gauss’s law in electrostatics. So this law can also be called as Gauss’s law in magnetism. The surface integral of ‘ magnetic field over a closed surface is zero. Mathematically,
\(\oint \overrightarrow{\mathrm{B}} \cdot d \overrightarrow{\mathrm{A}}=0\)
where \(\overrightarrow{\mathrm{B}}\) is the magnetic field. This equation implies that the magnetic lines of force form a continuous closed path. In other words, it means that no isolated magnetic monopole exists.

3. Third equation is Faraday’s law of electromagnetic induction. This law relates electric field with the changing magnetic flux which is mathematically written as
\(\oint \overrightarrow{\mathrm{E}} \cdot d \vec{l}=\frac{d}{d t} \Phi_{\mathrm{B}}\)
where \(\overrightarrow{\mathrm{E}}\) is the electric field. This equation implies that the line integral of the electric field around any closed path is equal to the rate of change of magnetic flux through the closed path bounded by the surface.

4. Fourth equation is modified Ampere’s circuital law. This is also known as ampere Maxwell’s law. This law relates the magnetic field around any closed path to the conduction current and displacement current through that path.
\(\oint \overrightarrow{\mathrm{B}} \cdot d \vec{l}=\mu_{0} \mathrm{I}_{\text {enclosed }}+\mu_{0} \varepsilon_{0} \int \overrightarrow{\mathrm{E}} \cdot \overrightarrow{d \mathrm{A}}\)
Where \(\overrightarrow{\mathrm{B}}\) is the magnetic field. This equation shows that both conduction and also displacement current produces magnetic field. These four equations are known as Maxwell’s equations in electrodynamics.

[OR]

Question 36.
(b) Obtain lens maker’s formula and mention its significance.
Answer:
Lens maker’s formula and lens equation: Let us consider a thin lens made up of a medium of refractive index n₂ is placed in a medium of refractive index n₁ . Let R₁ and R₂ be the radii of curvature of two spherical surfaces (1) and (2) respectively and P be the pole. Consider a point object O on the principal axis. The ray which falls very close to P, after refraction at the surface (1) forms image at I’. Before it does so, it is again refracted by the surface (2). Therefore the final image is formed at I. The general equation for the refraction at a spherical surface is given by

For the refracting surface (1), the light goes from to n₁ to n₂

If the object is at infinity, the image is formed at the focus of the lens. Thus, for u = oo, v =/ Then the equation becomes.

If the refractive index of the lens is n₂ and it is placed in air, then n₂ = n and n₁ = 1. So the equation (4) becomes,
\(\frac{1}{f}=(n-1)\left(\frac{1}{\mathrm{R}_{1}}-\frac{1}{\mathrm{R}_{2}}\right)\)

The above equation is called the lens maker’s formula, because it tells the lens manufactures what curvature is needed to make a lens of desired focal length with a material of particular refractive index. This formula holds good also for a concave lens. By comparing the equations (3) and (4) we can write,
\(\frac{1}{v}-\frac{1}{u}=\frac{1}{f}\) ……… (6)
This equation is known as lens equation which relates the object distance it and image distance v with the focal length / of the lens. This formula holds good for a any type of lens.

Question 37.
(a) Briefly discuss the observations of Hertz, Hallwachs and Lenard.
Answer:
Hertz observation:

• In 1887, Heinrich Hertz first became successful in generating and detecting electromagnetic wave with his high voltage induction coil to cause a spark discharge between two metallic spheres.
• When a spark is formed, the charges will oscillate back and forth rapidly and the electromagnetic waves are produced.
• The electromagnetic waves thus produced were detected by a detector that has a copper wire bent in the shape of a circle. Although the detection of waves is successful, there is a problem in observing the tiny spark produced in the detector.
• In order to improve the visibility of the spark, Hertz made many attempts and finally noticed an important thing that small detector spark became more vigorous when it was exposed to ultraviolet light.
• The reason for this behaviour of the spark was not known at that time. Later it was found that it is due to the photoelectric emission.
• Whenever ultraviolet light is incident on the metallic sphere, the electrons on the outer surface are emitted which caused the spark to be more vigorous.

Hallwachs’ observation:

• In 1888, Wilhelm Hallwachs, a German physicist, confirmed that the strange behaviour of the spark is due to the action of ultraviolet light with his simple experiment.
• A clean circular plate of zinc is mounted on an insulating stand and is attached to a gold leaf electroscope by a wire. When the uncharged zinc plate is irradiated by ultraviolet light from an arc lamp, it becomes positively charged and the leaves will open.
• Further, if the negatively charged zinc plate is exposed to ultraviolet light, the leaves will close as the charges leaked away quickly. If the plate is positively charged, it becomes more positive upon UV rays irradiation and the leaves will open further.
• From these observations, it was concluded that negatively charged electrons were emitted from the zinc plate under the action of ultraviolet light.

Lenard,s observation:
1. In 1902, Lenard studied this electron emission phenomenon in detail. The apparatus consists of two metallic plates A and C placed in an evacuated quartz bulb. The galvanometer G and battery B are connected in the circuit.

2. When ultraviolet light is incident on the negative plate C, an electric current flows in the circuit that is indicated by the deflection in the galvanorneter. On other hand, if the positive plate is irradiated by
the ultraviolet light, no current is observed in the circuit.

3. From these observations, it is concluded that when ultraviolet light falls on the negative plate. electrons are ejected from it which are attracted by the positive plate A. On reaching the positive plate through the evacuated bulb, the circuit is completed and the current flows in it.

4. Thus, the ultraviolet light falling on the negative plate causes the electron emission from
the surface of the plate.

[OR]

Question 37.
(b) Obtain the law of radioactivity.
Law of radioactive decay:
At any instant t, the number of decays per unit time, called rate of decay \(\left(\frac{d \mathrm{N}}{d t}\right)\) is proportional to the number of nuclei (N ) at the same instant.
\(\frac{d \mathrm{N}}{d t} \propto \mathrm{N}\)

By introducing a proportionality constant, the relation can be written as dN
\(\frac{d \mathrm{N}}{d t}=-\lambda \mathrm{N}\) ……… (1)

Here proportionality constant X is called decay constant which is different for different radioactive sample and the negative sign in the equation implies that the N is decreasing with time. By rewriting the equation (1), we get
dN = -λ Ndt …………(2)

Here dN represents the number of nuclei decaying in the time interval dt. Let us assume that at time t = 0 s, the number of nuclei present in the radioactive sample is N₀ . By integrating the equation (2), we can calculate the number of undecayed nuclei N at any time t.
From equation (2), we get

Taking exponentials on both sides, we get
N = N₀e^-λt …… (4)
[Note: e^lnx = e^y ⇒ x = e^y]

Equation (4) is called the law of radioactive decay. Here N denotes the number of undecayed nuclei present at any time t and N0 denotes the number of nuclei at initial time I = O. Note that the number of atoms is decreasing exponentially over the time. This implies that the time taken for all the radioactive nuclei to decay will be infinite. Equation (4) is plotted.
We can also define another useful quantity called activity (R) or decay rate which is the number of nuclei decayed per second and it is denoted as R = \(\left|\frac{d \mathbf{N}}{d t}\right|\)
Note: that activity R is a positive quantity. From equation (4), we get
R = \(\left|\frac{d \mathrm{N}}{d t}\right|=\lambda \mathrm{N}_{0} e^{-\lambda t}\) …… (5)
R = R₀e^-λt …………..(6)
where R₀ = λN₀
The equation (6) is also equivalent to radioactive law of decay. Here RQ is the activity of the sample at t = 0 and R is the activity of the sample at any time t. From equation (6), activity also shows exponential decay behavior. The activity R also can be expressed in terms of number of undecayed atoms present at any time t. From equation (6), since N = N₀ e^-λt we write
R = λN …………..(7)
Equation (4) implies that the activity at any time t is equal to the product of decay constant and number of undecayed nuclei at the same time t. Since N decreases over time, R also decreases.

Question 38.
(a) Describe the function of a transistor as an amplifier with the neat circuit diagram. Sketch the input and output wave form.
Answer:
Transistor as an amplifier:
A transistor operating in the active region has the capability to amplify weak signals. Amplification is the process of increasing the signal strength (increase in the amplitude). If a large amplification is required, the transistors are cascaded with coupling elements like resistors, capacitors, and transformers which is called as multistage amplifiers.

Here, the amplification of an electrical signal is explained with a single stage transistor amplifier as shown in figure (a). Single stage indicates that the circuit consists of one transistor with the allied components. An NPN transistor is connected in the common emitter configuration.

To start with, the Q point or the operating point of the transistor is fixed so as to get the maximum signal swing at the output (neither towards saturation point nor towards cut-off). A load resistance, R_c is connected in series with the collector circuit to measure the output voltage. The capacitor C₁ allows only the ac signal to pass through. The emitter bypass capacitor CE provides a low reactance path to the amplified ac signal. The coupling capacitor C_c is used to couple one stage of the amplifier with the next stage while constructing multistage amplifiers. V_s is the sinusoidal input signal source applied across the base-emitter. The output is taken across the collector-emitter.

Applying Kirchhoff ’s voltage law in the output loop, the collector-emitter voltage is given by
V_CE = V_CC – I_C R_C

Working of the amplifier:
During the positive half cycle
Input signal (V_s) increases the forward voltage across the emitter-base. As a result, the base current (I_B) increases. Consequently, the collector current (I_C) increases p times. This increases the voltage drop across R_C which in mm decreases the collector-emitter voltage (V_CE). Therefore, the input signal in the positive direction produces an amplified signal in the negative direction at the output. Hence, the output signal is reversed by 180° as shown in figure (b).

During the negative half cycle
Input signal (V_s) decreases the forward voltage across the emitter-base. As a result, base current (I_B) decreases and in turn increases the collector current (I_C). The increase in collector current (I_C) decreases the potential drop across R_c and increases the collector-emitter voltage ( V_CE). Thus, the input signal in the negative direction produces an amplified signal in the positive direction at the output. Therefore, 180° phase reversal is observed during the negative half cycle of the input signal.

[OR]

Question 38.
(b) Explain the three modes of propagation of electromagnetic waves through space.
Answer:
Propagation of electromagnetic waves:
The electromagnetic wave transmitted by the transmitter travels in three different modes to reach the receiver according to its frequency range:
1. Ground wave propagation (or) surface wave propagation (nearly 2 kHz to 2 MHz)
2. Sky wave propagation (or) ionospheric propagation (nearly 3 MHz to 30 MHz)
3. Space wave propagation (nearly 30 MHz to 400 GHz)

1. Ground wave propagation:
If the electromagnetic waves transmitted by the transmitter glide over the surface of the earth to reach the receiver, then the propagation is called ground wave propagation. The corresponding waves are called ground waves or surface waves.

Both transmitting and receiving antennas must be close to the earth. The size of the antenna plays a major role in deciding the efficiency of the radiation of signals. During transmission, the electrical signals are attenuated over a distance. Some reasons for attenuation are as follows:

Increasing distance: The attenuation of the signal depends on

• power of the transmitter
• frequency of the transmitter, and
• condition of the earth surface.

Absorption of energy by the Earth: When the transmitted signal in the form of EM wave is in contact with the Earth, it induces charges in the Earth and constitutes a current. Due to this, the earth behaves like a leaky capacitor which leads to the attenuation of the wave.

Tilting of the wave: As the wave progresses, the wavefront starts gradually tilting according to the curvature of the Earth. This increase in the ti It decreases the electric field strength of the wave. Finally, at some distance, the surface wave dies out due to energy loss.

The frequency of the ground waves is mostly less than 2 MHz as high frequency waves undergo more absorption of energy at the earth’s atmosphere. The medium wave signals received during the day time use surface wave propagation.

It is mainly used in local broadcasting, radio navigation, for ship-to-ship, ship-to-shore communication and mobile communication.

2. Sky Wave Propagation:
The mode of propagation in which the electromagnetic waves radiated from an antenna, directed upwards at large angles gets reflected by the ionosphere back to earth is called sky wave propagation or ionospheric propagation. The corresponding waves are called sky waves.

The frequency range of EM waves in this mode of propagation is 3 to 30 MHz. EM waves of frequency more than 30 MHz can easily penetrate through the ionosphere and does not undergo reflection. It is used for short wave broadcast services. Medium and high frequencies are for long-distance radio communication. Extremely long distance communication is also possible as the radio waves can undergo multiple reflections between the earth and the ionosphere. A single reflection helps the radio waves to travel a distance of approximately 4000 km.

Ionosphere acts as a reflecting surface. It is at a distance of approximately 50 km and spreads up to 400 km above the Earth surface. Due to the absorption of ultraviolet rays, cosmic ray, and other high energy radiations like a, p rays from sun, the air molecules in the ionosphere get ionized. This produces charged ions and these ions provide a reflecting medium for the reflection of radio waves or communication waves back to earth within the permitted frequency range. The phenomenon of bending the radio waves back to earth is nothing but the total internal reflection.

3. Space wave propagation:
The process of sending and receiving information signal through space is called space wave communication. The electromagnetic waves of very high frequencies above 30 MHz are called as space waves. These waves travel in a straight line from the transmitter to the receiver. Hence, it is used for a line of sight communication (LOS).

For high frequencies, the transmission towers must be high enough so that the transmitted and received signals (direct waves) will not encounter the curvature of the earth and hence travel with less attenuation and loss of signal strength. Certain waves reach the receiver after getting reflected from the ground.

Students can Download Tamil Nadu 12th Chemistry Model Question Paper 4 English Medium Pdf, Tamil Nadu 12th Chemistry Model Question Papers helps you to revise the complete Tamilnadu State Board New Syllabus and score more marks in your examinations.

TN State Board 12th Chemistry Model Question Paper 4 English Medium

Instructions:

1. The question paper comprises of four parts
2. You are to attempt all the parts. An internal choice of questions is provided wherever: applicable
3. All questions of Part I, II, III, and IV are to be attempted separately
4. Question numbers 1 to 15 in Part I are Multiple choice Questions of one mark each.  These are to be answered by choosing the most suitable answer from the given four alternatives and writing the option code and the corresponding answer
5. Question numbers 16 to 24 in Part II are two-mark questions. These are lo be answered in about one or two sentences.
6. Question numbers 25 to 33 in Part III are three-mark questions. These are lo be answered in about three to five short sentences.
7. Question numbers 34 to 38 in Part IV are five-mark questions. These are lo be answered in detail. Draw diagrams wherever necessary.

Time: 3 Hours
Maximum Marks: 70

Part-I

Answer all the questions. Choose the correct answer. [15 × 1 = 15]

Question 1.
The metal oxide which cannot be reduced to metal by carbon is ………………….
(a) PbO
(b) Al₂O₃
(C) ZnO
(d) FeO
Answer:
(b) Al₂O₃

Question 2.
Compounds used as an eye lotion .
(a) H₃BO₃
(b) HBO₂
(C) H₂B₄O₇
(d) B₂O₃
Answer:
(a) H₃BO₃

Question 3.
Which one of the following orders is correct for the bond dissociation enthalpy of halogen molecules?
(a) Br ₂> I₂ > F₂ > Cl₂
(b) F₂ > Cl₂ > Br₂ > I₂
(c) I₂ > Br₂ > Cl₂ > F₂
(d) Cl₂ > Br₂ > F₂ > I₂
Answer:
(d) Cl₂ > Br₂ > F₂ > I₂

Question 4.
Consider the following statements.
(i) The melting point decreases from Scandium to Vanadium in 3d series.
(ii) In 3d transition series, atomic radius decreases from Sc to V and upto copper atomic radius nearly remains the same.
(iii) As we move down in 3d transition series, atomic radius increases.
Which of the above statements is/are incorrect?
(a) i only
(b) ii only
(c) iii only
(d) i, ii and iii
Answer:
(a) i only

Question 5.
Which complex is used as an antitumor drug in cancer treatment?
(a) Ca – EDTA chelate
(b) EDTA
(c) Ti Cl₄ + Al(C₂H₅)₃
(d) Cis – Platin
Answer:
(b) EDTA

Question 6.
The number of unit cells in 8 gm of an element X ( atomic mass 40) which crystallizes in bcc
pattern is (N_A is the Avogadro number) ………..
(a) 6.023 x 10²³
(b) 6.023 x 10²²
(c) 60.23 x 10²³
(d) \(\left(\frac{6.023 \times 10^{23}}{8 \times 40}\right)\)

Hint: In bcc unit cell, 2 atoms = 1 unit cell
Number of atoms in 8g of element is Number of moles = \(\frac{8 g}{40 g, \mathrm{mol}^{-1}}\) = 0.2mol
1 mole contains 6.023 x 10²³ atoms 40g,mol
0.2 mole contains 0.2 x 6.023 x 10²³ atoms
\(\left(\frac{1 \text { unit cell }}{2 \text { atoms }}\right)\) x 0.2 x 6.023 xio23 = 6.023 x 10²² unit cells

Question 7.
Among the following graphs showing variation of rate constant with temperature (T) for a reaction, the one that exhibits Arrhenius behavior over the entire temperature range is …………
Answer:

Solution:
k = Ae^-(Ea/RT)
lnk = \(\ln \mathrm{A}-\left(\frac{\mathrm{E}_{\mathrm{a}}}{\mathrm{R}}\right)\left(\frac{1}{\mathrm{T}}\right)\)
this equation is in the form of a straight line equation y = c + m x
a plot of lnk vs (1/T) is a straight line with negative slope.

Question 8.
4Na+O₂ → 2Na₂O
Na₂O + H₂O → 2NaOH
In the given reaction, the oxide of sodium is …………..
(a) Acidic
(b) Basic
(c) Amphoteric
(d) Neutral
Answer:
(b) Basic
Solution:
Na₂O form NaOH so that it is basic oxide.

Question 9.
How many faradays of electricity are required for the following reaction to occur
MnO₄^– → Mn²⁺
(a) 5F
(b)3F
(e) 1F
(d) 7F
Answer:
(a) 5F
Hint: 7MnO₄^– + 5e^– → Mn²⁺4H2O
5 moles of electrons i.e., 5F charge is required.

Question 10.
Match the following:

Answer:
(a) A – (iv), B – (i), C – (ii), D – (iii)

Question 11.
Which of the following is not the product of dehydration of


Answer:

Question 12.
Which one of the following reaction is an example of disproportionation reaction?
(a) Aldol condensation
(b) cannizaro reaction
(c) Benzoin condensation
(d) none of these
Answer:
(b) cannizaro reaction

Question 13.
The correct order of basic strength in the case of substituted ethyl amines is ………

Answer:

Question 14.
Assertion: A solution of sucrose in water is dextrorotatory. But on hydrolysis in the presence
of little hydrochloric acid, it becomes levorotatory. –
Reason: Sucrose hydrolysis gives unequal amounts of glucose and fructose. As a result of this – change in sign of rotation is observed.
(a) If both accretion and reason are true and reason is the correct explanation of assertion
(b) If both assertion and reason are true but reason is not the correct explanation of assertion
(c) If assertion is true but reason is false
(d) if both assertion and reason are false
Answer:
(a) If both accretion and reason are true and reason is the correct explanation of assertion

Question 15.
The correct structure of the drug paracetamol is ……….
Tamil Nadu 12th Chemistry Model Question Paper 4 English Medium – 9
Answer:

Part – II

Answer any six questions. Question No. 20 is compulsory. [6 x 2 = 12]

Question 16.
What are the various steps involved in extraction of pure metals from their ores?
Answer:
The extraction of pure metals from the concentrated ores is carried out in two steps:

• Conversion of the ore into oxides of the metal of interest.
• Reduction of the metal oxides to elemental metals.

Question 17.
Why white phosphorous is also known as yellow phosphorous?
Answer:
The freshly prepared white phosphoms is colourless but becomes pale yellow due to formation of a layer of red phosphorus upon standing. Hence it is also known as yellow phosphoms.

Question 18.
Give an example of coordination compound used in medicine.
Answer:
Medical uses of coordination compounds : –

• Ca-EDTA chelate, is used in the treatment of lead and radioactive poisoning. That is for removing
  lead and radiactive metal ions from the body.
• Cis-platin is used as an antitumor drug in cancer treatment.

Question 19.
Give the examples for a zero order reaction.
Answer:
Examples for a zero order reaction:
(i) Photochemical reaction between H₂ and Cl₂

(ii) Decomposition of N20 on hot platinum surface
N₂ (g) ⇌ N₂ + 1/2O₂(g)

(iii) Iodination of acetone in acid medium is zero order with respect to iodine.

Question 20.
Write the overall redox reaction which takes place in the galvanic cell,
Pt(s) | Fe²⁺(aq),Fe³⁺(aq) | MnO^–₄(aq), H+(aq),Mn²⁺ (aq) | Pt(s)
Answer:
At Anode half cell : 5Fe²⁺_(aq) → 5Fe³⁺_(aq) + 5e^–
At cathode half cell : MnO^–_4(aq) + 8H⁺_(aq) + 5e^– → Mn²⁺_(aq) + 4H²O(l)
Overall redox reaction : 5Fe²⁺_(aq) + MnO^–_4(aq) + 8H⁺_(aq)→ 5Fe³⁺_(aq) + Mn²⁺_(aq) + 4H²O_(l)

Question 21.
In a coagulation experiment 10 mL of a colloid (X) is mixed with distilled water and 0.1M solution of an electrolyte AB so that the volume is 20 mL. It was found that all solutions containing more than 6.6 mL of AB coagulate with in 5 minutes. What is the flocculation values of AB for sol (X)?
Answer:
A minimum of 6.6mL of AB is required to coagulate the sol.
The moles of AB in the sol is, \(\frac{6.6 \times 0.01}{20}\) = 0.0033 moles
This means that a minimum of 0.033 moles or 0.0033 x 1000 = 3.3 milli moles are required
for coagulating one litre of sol.
Flocculation value of AB for X = 3.3

Question 22.
Explain Rosenmund reduction.
Answer:
Aldehydes can be prepared by the hydrogenation of acid chloride, in the presence of palladium supported by Barium sulphate. This reaction is called Rosenmund reduction.

In the above reaction, BaS04 act as a catalytic poison to palladium catalyst, so that aldehyde cannot be further reduced to alcohol.

Question 23.
‘What are the uses of aliphatic nitro compounds.
Answer:
(i) Nitromethane is used as a fuel for cars.
(ii) Chloropicrin (CCl₃NO₂) is used as an insecticide
(iii) Nitroethane is used as a fuel additive and precursor to explosive and they are good solvents for polymers, cellulose ester, synthetic rubber and dyes etc.

Question 24.
Classify the following as linear, branched or cross linked polymers
(a) Bakelite
(b) Nylon
(c) polythene
Answer:
(a) Bakelite – cross linked polymer
(b) Nylon – Linear polymer
(c) Polythene – Linear polymer

Part – III

Answer any six questions. Question No. 32 is compulsory. [6 x 3 = 18]

Question 25.
A hydride of 2^nd period alkali metal (A) on reaction with compound of Boron (B) to give a reducing agent (C). identify A, B and C.
Answer:
(i) A hydride of 2nd period alkali metal (A) is lithium hydride (LiH).
(ii) Lithium hydride (A) reacts with diborane (B) to give lithiumborohydride (C) which act as reducing agent.

Question 26.
Discuss the uses of phosphine.
Answer:
Phosphine is used for producing smoke screen as it gives large smoke. In a ship, a pierced . container with a mixture of calcium carbide and calcium phosphide, liberates phosphine and acetylene when thrown into sea. The liberated phosphine catches fire and ignites acetylene. These burning gases serves as a signal to the approaching ships. This is known as Holmes signal.

Question 27.
Calculate the percentage efficiency of packing in case of body centered cubic crystal.
Answer:
Packing efficiency : In body centered cubic arrangement the spheres are touching along the leading diagonal of the cube as shown in the figure.
In ∆ABC,
AC² = AB² + BC²
In∆ACG,
AG² = AC² + CG²

∴ Volume of the sphere with radius ‘r’


Number of spheres belong to a unit cell in bec arrangement is equal to two and hence the total volume of all spheres.

i. e., 68% of the available volume is occupied.The available space is used more efficiently than in simple cubic packing.

Question 28.
H₃BO₃ accepts hydroxide ion from water as shown below
H₃BO₃ (aq) + H₂O((l) ⇌ B(OH)₄^– + H⁺
Predict the nature of H₃BO₃ using Lewis concept.
Answer:
Boric acid is also called as hydrogen borate or orthoboric acid. It is a weak mono basic Lewis acid of boron and it is written as B(OH)₃ It accepts hydroxyl (OH^–) ion from water. It does not dissociate to give hydronium (H₃O⁺) ion rather forms metaborate ion and this ions in turn give H₃O⁺ ion.
B(OH)₃ + H₂O ⇌ [B(OH)₄]^– + H₃O⁺
Hence it is considered as weak acid.

Question 29.
Explain graphical representation of chemical adsorption and physical adsorption.
Answer:
(i) Adsorption isotherms represents the variation of adsorption at constant temperature.
(ii) When amount of adsorption is plotted versus temperature at constant pressure is called adsorption isobar

(iii) In physical adsorption x/m decreases with increase in T. But in chemical adsorption x/m increases with rise in temperature and then decreases. The increase illustrate the requirement of activation of the surface for adsorption is due to the fact that formation of activated complex require certain energy. The decrease at high temperature is due to desorption, as the kinetic energy of the adsorbate increases.

Question 30.
Mention the uses of Glycerol.
Answer:

• Glycerol is used as a sweetening agent in confectionery and beverages.
• It is used in the manufacture of cosmetics and transparent soaps.
• It is used in making printing inks and stamp pad ink and lubricant for watches and clocks.
• It is used in the manufacture of explosive like dynamite and cordite by mixing it with china clay.

Question 31.
Give the differences between primary and secondary structure of proteins.
Answer:
Primary structure of proteins:

• Linear sequence of amino acids
• Composed of peptide bonds formed between amino acids.
• Formed during translation.
• Involved in post – translational modifications.

Secondary structure of proteins :

• Folding of the peptide chain into an a-helix and p-sheet.
• Encompasses hydrogen bonds
• Forms collagen, elastin action, myosin, and keratin – like fibres.
• Involved in forming structures such as cartilages, ligaments, skins etc.

Question 32.
Draw the structure of (i) procaine (ii) Lidocaine
Answer:
(i) Procaine

(ii) Lidocaine

Question 33.
Explain the variation in E⁰_M3+/M2+ 3d series.
Answer:
1. In transition series, as we move down from Ti to Zn, the standard reduction potential \(\mathbf{E}^{0} \mathrm{M}^{2+} / \mathrm{M}^{3+}\) value is approaching towards less negative value and copper has a positive reduction potential, i.e. elemental copper is more stable than Cu²⁺ .

2. \(\mathrm{E}^{0} \mathrm{m}^{2+} / \mathrm{M}\) value for manganese and zinc are more negative than regular trend. It is due to extra stability arises due to the half filled d⁵ configuration in Mn²⁺ and completely filled d¹⁰ configuration in Zn²⁺.

3. The standard electrode potential for the M³⁺ / M²⁺ half cell gives the relative stability between M³⁺ and M²⁺.

4. The high reduction potential of Mn³⁺ / Mn²⁺ indicates Mn²⁺ is more stable than Mn³⁺.

5. For Fe³⁺ /Fe²⁺ the reductionpotential is 0.77V, and this low value indicates that both Fe³⁺ and Fe²⁺ can exist under normal condition.

6. Mn³⁺ has a 3d⁴ configuration while that of Mn²⁺ is 3d⁵. The extra stability associated with a half filled d sub-shell makes the reduction of Mn very feasible [E⁰ = +1.51 V]

Part – IV

Answer all the questions. [5 x 5 = 25]

Question 34.
(a) (i) Describe a method for refining nickel. (3)
(ii) Why group 18 elements are called inert gases?-Write the general electronic configuration of group 18 elements. (2)
[OR]
(b) (i) Give the uses of helium. (3)
(ii) Ni (II) compounds are more stable than Pt (II) compounds. Give reason. (2)
Answer:
(a) (i) The impure nickel is heated in a stream of carbon monoxide at around 350 K. The nickel
reacts with the CO to form a highly volatile nickel tetracarbonyl. The solid impurities ‘ . are left behind.
Ni (s) + 4 CO (g) → Ni(CO)₄ (g)
On heating the nickel tetracarbonyl around 460 K, the complex decomposes to give pure metal
Ni(CO)₄(g) → Ni(s) + 4 CO (g)

(ii) The elements of group-18 have completely filled s and p orbitals, hence they are more stable and have least reactivity. Therefore group-18 elements are called inert gases. ns2np6 is the general electronic configuration of group 18 elements.

[OR]

(b) (i) Uses of helium.

• Helium and oxygen mixture is used by divers in place of air oxygen mixture. This prevents the painful dangerous condition called bends.
• Helium is used to provide inert atmosphere in electric arc welding of metals
• Helium has lowest boiling point hence used in cryogenics (low temperature science).
• It is much less denser than air and hence used for filling air balloons

(ii) The ionisation enthalpy values can be used to predict the thermodynamic stability of their compounds.
For Nickel, I.E₁ + I.E₂ = 737 + 1753
= 2490 kJ mol-1
For Platinum, I.E₁ +I.E₂ = 864+ 1791
= 2655 kJ mol-1
Since, the energy required to form Ni²⁺ is less than that of Pt²⁺ , Ni(II) compounds are thermodynamically more stable than Pt(II) compounds.

Question 35.
(a) (i) Arrange the following in order of increasing molar conductivity (3)
1. Mg[Cr(NH₃)(Cl)₅] . 2.[Cr(NH₃)₅Cl]₃ [COF₆]₂ 3. [Cr(NH₃)₃Cl₃]
(ii) Silicon carbide is very hard. Justify this statement. (2)
[OR]
(b) (i) Write the rate law for the following reactions: (a) A reaction that is 3/2 order in x and zero order in y. (A) A reaction that is second order in NO and first order in Br₂. (3)
(ii) Classify the following species into Lewis acids and Lewis bases and show how these can act as Lewis acid / Lewis base? (2)
(a) OH^– ions (A) F^– (c) H⁺ (d) BCl₃
Answer:
(a) (i) These complexes can ionise in solution as:
Mg[Cr(NH₃)(Cl)₅] = Mg²⁺ + [Cr(NH₃)(Cl)₅]^2-
[Cr(NH₃ )₅Cl]₃ [COF₆]₂ = [Cr(NH₃)₅₆Cl]²⁺ + [COF₆]^3-
[Cr(NH₃)₃Cl₃] = does not ionize

As the number of ions in solution increases, their molar conductivity also increases.
Therefore, conductivity follows the order:
[Cr(NH₃)₃Cl₃] < [Cr(NH₃)₅Cl]₃ [COF < Mg[Cr(NH₃)(Cl)₅]

(ii) Silicon carbide is very hard. It is a covalent solid contains the atoms which are bound together in a three dimensional network entirely by covalent bonds. So the covalent network crystal siC is very hard and have high melting point.

[OR]

(b) (i)

(ii) (a) OH^– ions can donate an electron pair and act as Lewis base.
(b) F^– ions can donate an electron pair and act as Lewis base.
(c) H⁺ ions can accept an electron pair and act as Lewis base. .
(d) BCl₃ can accept an electron pair since Boron atom is electron deficient. It is a Lewis acid.

Question 36.
(a) (z) Calculate pH of 10^-7 MHCl. (3)
(ii) Define corrosion. Give one example. (2)
[OR]
(b) What is adsorption isotherm? Explain about Freundlich adsorption isotherm. (5)
Answer:
(a) (z) If we do not consider [H₃O⁺ ] from the ionisation of H₂O, then [H₃O⁺ ] = [HCl] = 10^-7 M i.e., pH = 7, which is a pH of a neutral solution. We know that HCl solution is acidic whatever may be the concentration of HCl i.e, the pH value should be less than 7. In this case the concentration of the acid is very low (10^-7 M). Hence, the H₃O⁺ (10^-7 M) formed due to the auto ionisation of water cannot be neglected.
So, in this case we should consider [H₃O⁺ ] from ionisation of H₂ O
[H₃O⁺ ] = 10^-7 (from HCl) + 10^-7 (from water)
= 10^-7 (1+1)
= 2 x 10^-7
pH = -log₁₀[H₃O⁺]
= log₁₀ (2 x 10^-7 )=—[log 2 + log10^-7 ]
= – log 2 -(-7). 1og₁₀¹⁰
= 7 – log 2
= 7 – 0.3010 = 6.6990
= 6.70

(ii) The redox process which causes the deterioration of metal is called corrosion.
Rusting of iron is an example of corrosion. It is an electro chemical process.

[OR]

(b) i. Adsorption isotherms represents the variation of adsorption at constant temperature. Adsorption isotherm can be studied quantitatively. ii. A plot between the amount of adsorbate adsorbed and pressure or concentration of adsorbate at constant temperature is called adsorption isotherms.

ii. Freundlich adsorption isotherm.
According to Freundlich \(\frac{\mathbf{x}}{\mathrm{m}}=\mathrm{k} \mathrm{P}^{1 / \mathrm{n}}\)
Where x is the amount of adsorbate (or) adsorbed on ‘m’ gm of adsorbent at a pressure of R k and n are constants. Value of ‘n’ is always less than unity.

iv. This equation is applicable for adsorption of gases on solid surfaces. The Same equation becomes \(\frac{\mathbf{x}}{\mathrm{m}}=\mathrm{k} \mathrm{P}^{1 / \mathrm{n}}\) kc when used for adsorption in solutions with ‘c’ as concentration.

v. These equation quantitatively predict the effect of pressure (or concentration) on the adsorption of gases (or adsorbates) at constant temperature.

vi. Taking log on both sides of equation

vii. Hence the intercept represents the value of log k and the slope \(\frac{b}{q}\) gives \(\frac{1}{n}\)

viii. This equation explains the increase of \(\frac{x}{m}\)with increase in pressure. But experimental values shows the deviation at low pressure.

ix. Limitations:
(a) This equation is purely empirical and valid over a limited pressure range.
(b) The value of k and n also found vary with temperatures. No theoretical explanations were given.

Question 37.
(a) An organic compound (A) of molecular formula C₆H₆O gives white precipitate with bromine water. (A) on reaction with NaOH gives (B). (B) reacts with methyl iodide in presence of dry ether gives (C) of molecular formula C₇H_/8O which will not liberate H2 gas with metallic Na. (C) on reaction with acetyl chloride gives (D) and (E) of formula which are position isomers. Identify A, B, C, D & E and explain the reaction. (5)

[OR]

(A) (i) What happens when n-propyl benzene is oxidised using H⁺ / KMnO₄?(2)
(ii) Identify A, B ,and C.

Answer:
1. An organic compound gives white precipitate with bromine water means it must be a phenol. From the molecular formula it is identified as C₆H₅OH.

2. Phenol on reaction with NaOH gives (B) as sodium phenoxide C₆H₅ONa.

3. Sodium phenoxide on reaction with methyl iodide in the pressure of dry ether undergo Williamsons synthesis and gives Anisole as (C).

4. Anisole on reaction with acetyl chloride undergoes Friedel Craft’s acetylation and yield o-methoxy acetophenone and p-methoxy acetophenone as (D) and (E).


(b)

Question 38.
(a) (i) How will you distinguish between primary secondary and tertiary alphatic amines. (3)
(ii) Convert Benzene diazonium chloride into phenol. (2)
[OR]
(b) (i) What are the functions of lipids in living organism? (3)
(ii) What is Orion? Give its preparation and use. (2)
Answer:
(a) (i)

Students can Download Computer Science Chapter 11 Database Concept Questions and Answers, Notes Pdf, Samacheer Kalvi 12th Computer Science Book Solutions Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 12th Computer Science Solutions Chapter 11 Database Concept

Samacheer Kalvi 12th Computer Science Database Concept Text Book Back Questions and Answers

PART – 1
I. Choose The Best Answer

Question 1.
What is the acronym of DBMS?
Answer:
(a) DataBase Management Symbol
(b) Database Managing System
(c) DataBase Management System
(d) DataBasic Management System
Answer:
(c) DataBase Management System

Question 2.
A table is known as ……………………..
(a) tuple
(b) attribute
(c) relation
(d) entity
Answer:
(c) relation

Question 3.
Which database model represents parent-child relationship?
(a) Relational
(b) Network
(c) Hierarchical
(d) Object
Answer:
(c) Hierarchical

Question 4.
Relational database model was first proposed by ……………………..
(a) E F Codd
(b) E E Codd
(c) c) E F Cadd
(d) E F Codder
Answer:
(a) E F Codd

Question 5.
What type of relationship does hierarchical model represents?
(a) one-to-one
(b) one-to-many
(c) many-to-one
(d) many-to-many
Answer:
(b) one-to-many

Question 6.
Who is called Father of Relational Database from the following?
(a) Chris Date
(b) Hugh Darween
(c) Edgar Frank Codd
(d) Edgar Frank Cadd
Answer:
(c) Edgar Frank Codd

Question 7.
Which of the following is an RDBMS?
(a) Dbase
(b) Foxpro
(c) Microsoft Access
(d) SQLite
Answer:
(d) SQLite

Question 8.
What symbol is used for SELECT statement?
(a) σ
(b) π
(c) X
(d) Ω
Answer:
(a) σ

Question 9.
A tuple is also known as ………………………
(a) table
(b) row
(c) attribute
(d) field
Answer:
(b) row

Question 10.
Who developed ER model?
(a) Chen
(b) EF Codd
(c) Chend
(d) Chand
Answer:
(a) Chen

PART – II
II. Answer The Following Questions

Question 1.
Mention few examples of a database?
Answer:
Examples of popular DBMS: Dbase, FoxPro

Question 2.
List some examples of RDBMS?
Answer:
SQL server, Oracle, mysql, MariaDB, SQLite.

Question 3.
What is data consistency?
Answer:
Data Consistency
On live data, it is being continuously updated and added, maintaining the consistency of data can become a challenge. But DBMS handles it by itself. Data Consistency means that data values are the same at all instances of a database

Question 4.
What is the difference between Hierarchical and Network data model?
Answer:
Network database model is an extended form of hierarchical data model. The difference between hierarchical and Network data model is :

1. In hierarchical model, a child record has only one parent node,
2. In a Network model, a child may have many parent nodes. It represents the data in many-to-many relationships.
3. This model is easier and faster to access the data.

Question 5.
What is normalization?
Answer:

1. Normalization is a process of organizing the data in the database to avoid data redundancy and to improve data integrity.
2. Database normalization was first proposed by Dr. Edgar F Codd as an integral part of RDBMS. These rules are known as E F Codd Rules.

PART – III
III. Answer The Following Questions

Question 1.
What is the difference between Select and Project command?
Answer:
Select:
THE SELECT operation is used for selecting a subset with tuples according to a given condition. Select filters out all tuples that do not satisfy C.

Project:
The projection eliminates all attributes of the input relation but those mentioned in the projection list. The projection method defines a relation that contains a vertical subset of Relation.

Question 2.
What is the role of DBA?
Answer:
Database Administrator

1. Database Administrator or DBA is the one who manages the complete database management system.
2. DBA takes care of the security of the DBMS, managing the license keys, managing user accounts and access etc.

Question 3.
Explain Cartesian Product with a suitable example?
PRODUCT OR CARTESIAN PRODUCT (Symbol: X)
Answer:
Cross product is a way of combining two relations. The resulting relation contains, both relations being combined.
A × B means A times B, where the relation A and B have different attributes.
This type of operation is helpful to merge columns from two relations.

Question 4.
Explain Object Model with example?
Answer:
Object Model

1. Object model stores the data in the form of objects, attributes and methods, classes and Inheritance.
2. O This model handles more complex applications, such as Geographic information System (GIS), scientific experiments, engineering design and manufacturing.
3. It is used in file Management System.
4. It represents real world objects, attributes and behaviors. It provides a clear modular structure.
5. It is easy to maintain and modify the existing code.

An example of the Object model is Shape, Circle, Rectangle and Triangle are all objects in this model.

1. Circle has the attribute radius.
2. Rectangle has the attributes length and breadth.
3. Triangle has the attributes base and height.
4. The objects Circle, Rectangle and Triangle inherit from the object Shape.

Question 5.
Write a note on different types of DBMS users?
Answer:
Types of DBMS Users
(i) Database Administrator:
Database Administrator or DBA is the one who manages the complete database management system. DBA takes care of the security of the DBMS, managing the license keys, managing user accounts and access etc.

(ii) Application Programmers or Software Developers:
This user group is involved in developing and designing the parts of DBMS.

(iii) End User:
End users are the one who store, retrieve, update and delete data.

(iv) Database designers: are responsible for identifying the data to be stored in the database for choosing appropriate structures to represent and store the data.

PART – IV
IV. Answer The Following Questions

Question 1.
Explain the different types of data model?
Answer:
Types of Data Model
Following are the different types of a Data Model

1. Hierarchical Model
2. Relational Model
3. Network Database Model
4. Entity Relationship Model
5. Object Model

1. Hierarchical Model
Hierarchical model was developed by IBM as Information Management System.
In Hierarchical model, data is represented as a simple tree like structure form. This model represents a one-to-many relationship i.e. parent-child relationship. One child can have only one parent but one parent can have many children. This model is mainly used in IBM Main Frame computers.

2. Relational Model
The Relational Database model was first proposed by E.F. Codd in 1970 . Nowadays, it is the most widespread data model used for database applications around the world.
The basic structure of data in relational model is tables (relations). All the information’s related to a particular type is stored in rows of that table. Hence tables are also known as relations in a relational model. A relation key is an attribute which uniquely identifies a particular tuple (row in a relation (table)).

3. Network Model
Network database model is an extended form of hierarchical data model. The difference between hierarchical and-Network data model is :

1. In hierarchical model, a child record has only one parent node,
2. In a Network model, a child may have many parent nodes. It represents the data in many-to-many relationships.
3. This model is easier and faster to access the data.

School represents the parent node
Library, Office and Staff room is a child to school (parent node)
Student is a child to library, office and staff room (one to many relationship)

4. Entity Relationship Model. (ER model)
In this database model, relationship are created by dividing the object into entity and its characteristics into attributes.
It was developed by Chen in 1976. This model is useful in developing a conceptual design for the database. It is very simple and easy to design logical view of data. The developer can easily understand the system by looking at ER Model constructed. Rectangle represents the entities. E.g. Doctor and Patient

Ellipse represents the attributes E.g. D-id, D-name, P-id, P-name. Attributes describes the characteristics and each entity becomes a major part of the data stored in the database. Diamond represents the relationship in ER diagrams E.g. Doctor diagnosis the Patient

5. Object Model
Object model stores the data in the form of objects, attributes and methods, classes and Inheritance. This model handles more complex applications, such as Geographic information System (GIS), scientific experiments, engineering design and manufacturing. It is used in file Management System. It represents real world objects, attributes and behaviors. It provides a clear modular structure. It is easy to maintain and modify the existing code.

Question 2.
Explain the different types of relationship mapping?
Answer:
Types of Relationships:
Following are the types of relationships used in a database.

1. One-to-One Relationship
2. One-to-Many Relationship
3. Many-to-One Relationship
4. Many-to-Many Relationship

1. One-to-One Relationship
In One-to-One Relationship, one entity is related with only one other entity. One row in a table is linked with only one row in another table and vice versa.
For example: A student can have only one exam number.

2. One-to-Many Relationship
In One-to-Many relationship, one entity is related to many other entities. One row in a table A is linked to many rows in a table B, but one row in a table B is linked to only one row in table A. For example: One Department has many staff members.

3. Many-to-One Relationship
In Many-to-One Relationship, many entities can be related with only one in the other entity. For example: A number of staff members working in one Department. Multiple rows in staff members table is related with only one row in Department table.

4. Many-to-Many Relationship
Amany-to-many relationship occurs when multiple records in a table are associated with multiple records in another table.

Example 1: Customers and Product:
Customers can purchase various products and Products can be purchased by many customers

Example 2: Students and Courses:
A student can register for many Courses and a Course may include many students

Example 3: Books and Student:
Many Books in students.

Question 3.
Differentiate DBMS and RDBMS?
Answer:

Question 4.
Explain the different operators in Relational algebra with suitable examples?
Answer:
Relational Algebra Operations from Set Theory

1. UNION (∪)
2. INTERSECTION (∩)
3. DIFFERENCE (-)
4. CARTESIAN PRODUCT (X)

SELECT (symbol: σ)
General form σ_c ( R) with a relation R and a condition C on the attributes of R.
The SELECT operation is used for selecting a subset with tuples according to a given condition. Select filters out all tuples that do not satisfy C.

PROJECT (symbol : II)
The projection eliminates all attributes of the input relation but those mentioned in the projection list.
Example 1 using Table A
π_course (STUDENT)
Result

Course Big Data R language PythonProgramming
Note: duplicate row is removed in the result UNION (Symbol :u)
It includes all tuples that are in tables A or in B. It also eliminates duplicates. Set A Union Set B would be expressed asAuB

Example 2:
Consider the following tables

Result

SET DIFFERENCE ( Symbol: -)
The result of A – B, is a relation which includes all tuples that are in A but not in B. The attribute name of A has to match with the attribute name in B.

Example 4:
( using Table B)
Result

INTERSECTION (symbol: ∩) A∩B
Defines a relation consisting of a set of all tuple that are in both in A and B. However, A and B must be union-compatible

Example 5:
(using Table B)

PRODUCT OR CARTESIAN PRODUCT (Symbol: X)
Cross product is a way of combining two relations. The resulting relation contains, both relations being combined.
A × B means A times B, where the relation A and B have different attributes.
This type of operation is helpful to merge columns from two relations.

Cartesian product : Table A × Table B

Question 5.
Explain the characteristics of DBMS?
Characteristics of Database Management System
Answer:

Samacheer kalvi 12th Computer Science Database Concept Additional Questions and Answers

PART – I
I. Choose The Correct Answer

Question 1.
…………………… are raw facts stored in a computer
(a) data
(b) Information
(c) row
(d) tuple
Answer:
(a) data

Question 2.
……………………. gives meaningful information
(a) data
(b) Information
(c) row
(d) tuple
Answer:
(b) Information

Question 3.
……………………. is a repository collection of related data
(a) data
(b) Information
(c) database
(d) tuple
Answer:
(c) database

Question 4.
……………………… is a software that allows us to create, define and manipulate databases
(a) data
(b) Information
(c) DBMS
(d) Tuple
Answer:
(c) DBMS

Question 5.
Which one of the following is not a characteristic of DBMS?
(a) Redundancy
(b) consistency
(c) Normalization
(d) Insecure
Answer:
(d) Insecure

Question 6.
Find the wrong statement about DBMS?
(a) segregation of application program
(b) Maximum data Redundancy
(c) Easy retrieval of data
(d) Reduced development time
Answer:
(b) Maximum data Redundancy

Question 7.
How many major components of DBMS are there?
(a) 2
(b) 3
(c) 4
(d) 5
Answer:
(d) 5

Question 8.
Which one of the following is not a component of DBMS?
(a) Data
(b) Methods
(c) DataBase Access Language
(d) Modules
Answer:
(d) Modules

Question 9.
Which is the language used to write commands to access, insert, update data stored in database?
(a) DataBase Access Languages
(b) Javascript
(c) Basic
(d) Foxpro
Answer:
(a) DataBase Access Languages

Question 10.
A column is known as an ……………………….
Answer:
Attribute

Question 11.
Entire collection of related data in one table, is referred to as ……………………… or …………………………
Answer:
File or Table

Question 12.
Each table ………………………. represents a Field
Answer:
column

Question 13.
Each ……………………… in table represents a record.
Answer:
row

Question 14.
How many different types of a data model are there?
(a) 2
(b) 3
(c) 4
(d) 5
Answer:
(d) 5

Question 15.
Hierarchical Model was developed by ……………………….
(a) Apple
(b) IBM
(c) Microsoft
(d) Macromedia
Answer:
(b) IBM

Question 16.
Which database Model is the extended form of hierarchical data Model?
(a) Network
(b) Relational
(c) Flat File
(d) Object
Answer:
(a) Network

Question 17.
1. Relational – (i) classes
2. object model – (ii) Mainframe
3. ER model – (iii) key
4. Hierarchical – (iv) Entity
(a) 1-iii, 2-i, 3-iv, 4-ii
(b) 1-i, 2-ii, 3-iii, 4-iv
(c) 1-iv, 2-iii, 3-i, 4-ii
(d) 1-iv, 2-ii, 3-i, 4-iii
Answer:
(a) 1-iii, 2-i, 3-iv, 4-ii

Question 18.
The relational model was developed in the year ……………………..
(a) 1980
(b) 1970
(c) 1965
(d) 1985
Answer:
(b) 1970

Question 19.
…………………… uniquely identifies a particular tuple in a table
Answer:
Relation key

Question 20.
Which model establishes many to many relationships?
(a) Network
(b) Relational
(c) Hierarchical
(d) Object
Answer:
(a) Network

Question 21.
ER Model Expand ………………………..
(a) Entry Relation
(b) Entity Relationship
(c) Entire Row
(d) Entity Row
Answer:
(b) Entity Relationship

Question 22.
ER Model was developed in the year …………………….
(a) 1978
(b) 1972
(c) 1976
(d) 1975
Answer:
(c) 1976

Question 23.
In ER Model, objects are said to be ……………………..
Answer:
entity

Question 24.
Find the wrongly matched pair.
(a) Entities – Rectangle
(b) Ellipse – attributes
(c) Diamond – relationship
(d) row – square
Answer:
(d) row – square

Question 25.
…………………….. represents the relationship in ER diagrams.
Answer:
Diamonds

Question 26.
GIS stands for ………………………
Answer:
Geographic Information System

Question 27.
Which model is used in file management systems?
(a) object
(b) Hierarchical
(c) Network
(d) ER
Answer:
(a) object

Question 28.
DBA means ………………….
Answer:
Database Administators

Question 29.
………………….. is one who manages the complete database management system
(a) Manager
(b) Engineer
(c) DBA
(d) Service Person
Answer:
(c) DBA

Question 30.
……………………. are the one who store, retrieve, update and delete data.
Answer:
End User

Question 31.
Choosing appropriate structures to represent and store the data are the task of ……………………..
Answer:
database designer

Question 32.
RDBMS means ………………………..
(a) Relational Database Manipulation System
(b) Relational Database Management system
(c) Rapid DataBase Management Server
Answer:
(b) Relational Database Management system

Question 33.
Pick the odd out.
Oracle, Foxpro, MariaDB, SQLite
Answer:
Foxpro

Question 34.
Find the true statement
(a) Data redundancy is exhibited by DBMS
(b) Data redundancy is not present in DBMS
Answer:
(a) Data redundancy is exhibited by DBMS

Question 35.
Find the false statement
(a) Distributed Databases supported by DBMS
(b) Distributed Databases supported by RDBMS
Answer:
(a) Distributed Databases supported by DBMS

Question 36.
……………………. Model of data storage is used in DBMS.
Answer:
Navigational

Question 37.
In which database systems, transaction management is efficient?
(a) DBMS
(b) RDBMS
(c) ERDMS
(d) DBMS
Answer:
(b) RDBMS

Question 38.
How many types of relationships are there?
(a) 1
(b) 2
(c) 3
(d) 4
Answer:
(d) 4

Question 39.
Identify which one of the following is an example for many to one relationship?
(a) student with exam number
(b) many staff members in one department
(c) customer, products
(d) Books and students
Answer:
(b) many staff members in one department

Question 40.
…………………… is a procedural query language used to query the database tables using SQL
Answer:
Relational Algebra

Question 41.
Find the wrong pair
(a) Union U
(b) cartesian product P
(c) project n
(d) select o
Answer:
(b) cartesian product P

Question 42.
Which method defines a relation that contains a vertical subset of relation?
(a) project
(b) select
(c) difference
(d) union
Answer:
(a) project

Question 43.
Duplicate row is removed in ……………………….
(a) o
(b) π
(c) x
(d) –
Answer:
(b) π

Question 44.
…………………. is used to merge columns from two relations.
(a) σ
(b) π
(c) x
(d) –
Answer:
(c) x

Question 45.
…………………. is security from unauthorized users.
Answer:
Data Integrity

Question 46.
…………………. means duplication of data in a database.
Answer:
Redundancy.

PART- II
II. Answer The Following Questions

Question 1.
Differentiate data from Information?
Answer:
Data:
Data are raw facts stored in a computer. A data may contain any character, text, word or a number.
Example:
600006, DPI Campus, SCERT, Chennai, College Road

Information:
Information is formatted data, which allows to be utilized in a significant way. It gives meaningful information.
Example:
SCERT
College Road
DPI Campus
Chennai 600006

Question 2.
Define database?
Answer:
Database is a repository collection of related data organized in a way that data can be easily accessed, managed and updated. Database can be a software or hardware based, with one sole purpose of storing data.

Question 3.
Name the components of DBMS?
Answer:
Components of DBMS:
The Database Management System can be divided into five major components as follows:

1. Hardware
2. Software
3. Data
4. Procedures/Methods
5. Database Access Languages

Question 4.
Define Table?
Answer:
Table is the entire collection of related data in one table, referred to as a File or Table where the data is organized as row and column.

Question 5.
Define row and column?
Answer:
Each row in a table represents a record, which is a set of data for each database entry. Each table column represents a Field, which groups each piece or item of data among the records into specific categories or types of data. Eg. StuNo., StuName, StuAge, StuClass, StuSec.

Question 6.
What is meant by data model?
Answer:
Data Model

1. A data model describes how the data can be represented and accessed from a software after complete implementation
2. It is a simple abstraction of complex real world data gathering environment.
3. The main purpose of data model is to give an idea as how the final system or software will look like after development is completed..

Question 7.
Write note on relational Algebra?
Answer:
Relational Algebra is a procedural query language used to query the database tables using SQL. Relational algebra operations are performed recursively on a relation (table) to yield an output.

PART – III
III. Answer The Following Questions

Question 1.
Define DBMS?
Answer:
A DBMS is a software that allows us to create, define and manipulate database, allowing users to store, process and analyze data easily. DBMS provides us with an interface or a tool, to perform various operations to create a database, storing of data and for updating data, etc. DBMS also provides protection and security to the databases. It also maintains data consistency in case of multiple users.

Question 2.
What are the advantages of DBMS?
Answer:
Advantages of DBMS

1. Segregation of application program
2. Minimal data duplication or Data Redundancy
3. Easy retrieval of data using the Query Language
4. Reduced development time and maintenance

PART – IV
IV. Answer The Following Questions

Question 1.
Explain the Various Components of DBMS?
Answer:
Components of DBMS:
The Database Management System can be divided into five major components as follows:

1. Hardware
2. Software
3. Data
4. Procedures/Methods
5. Database Access Languages

1. Hardware:
The computer, hard disk, I/O channels for data, and any other physical component involved in storage of data

2. Software:
This main component is. a program that controls everything. The DBMS software is capable of understanding the Database Access Languages and interprets into database commands for execution.

3. Data:
It is that resource for which DBMS is designed. DBMS creation is to store and utilize data.

4. Procedures/Methods:
They are general instructions to use a database management system such as installation of DBMS, manage databases to take backups, report generation, etc.

5. DataBase Access Languages:
They are the languages used to write commands to access, insert, update and delete data stored in any database.

Students can Download Computer Science Chapter 10 Python Classes and Objects Questions and Answers, Notes Pdf, Samacheer Kalvi 12th Computer Science Book Solutions Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 12th Computer Science Solutions Chapter 10 Python Classes and Objects

Samacheer Kalvi 12th Computer Science Python Classes and Objects Text Book Back Questions and Answers

PART – 1
I. Choose The Best Answer

Question 1.
Which of the following are the key features of an Object Oriented Programming language?
(a) Constructor and Classes
(b) Constructor and Object
(c) Classes and Objects
(d) Constructor and Destructor
Answer:
(c) Classes and Objects

Question 2.
Functions defined inside a class:
(a) Functions
(b) Module
(c) Methods
(d) section
Answer:
(c) Methods

Question 3.
Class members are accessed through which operator?
(a) &
(b) .
(c) #
(d) %
Answer:
(b) .

Question 4.
Which of the following method is automatically executed when an object is created?
(a) _object_( )
(b) _del( )_( )
(c) _func_( )
(d) _init_( )
Answer:
(d) _init_( )

Question 5.
A private class variable is prefixed with
(a) _
(b) &&
(c) ##
(d) **
Answer:
(a) _

Question 6.
Which of the following method is used as destructor?
(a) _init_( )
(b) _dest_ ( )
(c) _rem_( )
(d) _del_( )
Answer:
(d) _del_( )

Question 7.
Which of the following class declaration is correct?
(a) class class_name
(b) class class_name< >
(c) class class_name:
(d) class class_name[ ]
Answer:
(c) class class_name:

Question 8.
Which of the following is the output of the following program?
– class Student:
def_init_(self, name):
self.name=name
S=Student(“Tamil”)
(a) Error
(b) Tamil
(c) name
Answer:
(b) Tamil

Question 9.
Which of the following is the private class variable?
(a) _num
(b) ##num
(c) $$num
(d) &&num
Answer:
(a) _num

Question 10.
The process of creating an object is called as:
(a) Constructor
(b) Destructor
(c) Initialize
(d) Instantiation
Answer:
(d) Instantiation

PART – II
II. Answer The Following Questions

Question 1.
What is class?
Answer:
Classes and Objects are the key features of Object Oriented Programming. Class is the main building block in Python. Object is a collection of data and function that act on those data. Class is a template for the object. According to the concept of Object Oriented Programming, objects are also called as instances of a class or class variable.

Question 2.
What is instantiation?
Answer:
Once a class is created, next you should create an object or instance of that class. The process of creating object is called as “Class Instantiation”.
Syntax:
object_name = class_name( )

Question 3.
What is the output of the following program?
Answer:
class Sample:
_num=10
def disp(self):
print(self._num)
S=Sample( )
S.disp( )
print(S._num)
Output:
Error: Sample has no attribute S._num
10

Question 4.
How will you create constructor in Python?
Answer:
In Python, there is a special function called “init” which act as a Constructor. It must begin and end with double underscore. This function will act as an ordinary function;
General format of init method (Constructor function)
def_init_(self.[args …………….]):
<statements>

Question 5.
What is the purpose of Destructor?
Answer:
Destructor is also a special method gets executed automatically when an object exit from the scope. It is just opposite to constructor. In Python, _del_( ) method is used as destructor.

PART – III
III. Answer The Following Questions

Question 1.
What are class members? How do you define it?
Answer:
In Python, a class is defined by using the keyword class. Every class has a unique name followed by a colon ( : ).
Syntax:
class class_name:
statement_1
statement_2
…………………
…………………
statement_n
Where, statement in a class definition may be a variable declaration, decision control, loop or even a function definition. Variables defined inside a class are called as “Class Variable” and functions are called as “Methods”. Class variable and methods are together known as members of the class. The class members should be accessed through objects or instance of class. A class can be defined anywhere in a Python program.
Example:
Program to define a class
class Sample:
x, y = 10, 20 # class variables
In the above code, name of the class is Sample and it has two variables x and y having the initial value 10 and 20 respectively. To access the values defined inside the class, you need an object or instance of the class.

Question 2.
Write a class with two private class variables and print the sum using a method?
Answer:
class Sample:
def_init_(self,n1,n2):
self._n1=n1
self._n2=n2
def display(self):
print(“class variable 1:”, self._n1)
print(“class variable 2:”, self._n2)
print(“sum self._n1 + self._n2)
s = sample(10, 20)
s.display( )
Output:
class variable 1 : 10
class variable 2 : 20
sum : 30

Question 3.
Find the error in the following program to get the given output?
class Fruits:
def_init_(self, f1, f2):
self.f1=f1
self.f2=f2
def display (self):
print(“Fruit 1 = %s, Fruit 2 = %s” %(self.fl, self.f2))
F = Fruits (‘Apple’, ‘Mango’)
del F.display
F.display( )
Output
Fruit 1 = Apple, Fruit 2 = Mango
Answer:
In line No. 8, del F.display will not come

Question 4.
What is the output of the following program?
Answer:
class Greeting:
def_init_(self, name):
self._name = name
def display(self):
print(“Good Morning “, self._name)
obj=Greeting(‘Bindu Madhavan’)
obj.display( )
Output:
Bindu Madhavan Good Morning

Question 5.
How do define constructor and destructor in Python?
Answer:
General format of init method (Constructor function)
def_init_(self.[args ……………….]):
<statements>
To define destructor:
_del_ ( ) method is used.

PART – IV
IV. Answer The Following Questions

Question 1.
Write a menu driven program to add or delete stationary items. You should use dictionary to store items and the brand?
Answer:
stationary = { }
while((ch == 1) or (ch == 2))
print(” 1. Add Item \n 2. Delete Item”)
ch = int(input(“Enter your choice “))
if(ch==1):
n = int(input(“Enter the number of items to be added in the stationary shop”))
for i in range(n):
item = input(“Enter an item “)
brand = input(“Enter the brand Name”)
stationary[item] = brand
print(stationary)
elif(ch == 2):
remitem = input(“Enter the item to be deleted from the shop”)
dict.pop(remitem)
print( stationary)
else:
print(“Invalid options. Type 1 to add items and 2 to remove items “)
ch = int(input(“Enter your choice :”)
Output:

1. Add item
2. Delete Item Enter your choice : 1

Enter the number of items to be added in the stationary shop : 2
Enter an item : Pen
Enter the brand Name : Trimax
Enter an item : Eraser
Enter the brand Name : Camlin
Pen : Trimax
Eraser : Camlin
Enter your choice : 2
Enter the item to be deleted from the shop : Eraser
Pen : Trimax
Enter your choice : 3
Invalid options. Type 1 to add items an 2 to remove items.

Practice Programs

Question 1.
Write a program using class to store name and marks of students in list and print total marks?
Answer:
class stud:
def_init_(self):
self.name=” ”
self.m1=0
self.m2=0
self.tot=0
def gdata(self):
self.name = input(“Enter your name”)
self.m1 = int(input(“Enter marks 1”))
self.m2 = int(input(“Enter marks2”))
self, tot = self.m1+self.m2
def disp(self):
print(self.name)
print(self.m1)
print(self.m2)
print(self.tot)
mlist = [ ]
st = stud( )
st.gdata( )
mlist. append(st)
for x in mlist:
x.disp( )
Output:
Enter your name Ram
Enter marks 1 100
Enter marks2 100
Ram 100 100 200

Question 2.
Write a program using class to accept three sides of a triangle and print its area?
Answer:
class Tr:
def_init_(self, a, b, c):
self.a = float(a)
self.b = float(b)
self.c = float(c)
def area(self):
s = (self.a + self.b + self.c)/2
return((s*(s-self.a) * (s-self.b) * (s-self.c) ** 0.5)
a = input(“Enter side 1:”)
b = input(“Enter side2:”)
c = input(“Enter side3:”)
ans=Tr(a,b,c)
print(ans.area( ))
Output:
Enter side 1 : 3
Enter side 2 : 4
Enter side 3 : 5
6.0

Question 3.
Write a menu driven program to read, display, add and subtract two distances?
Answer:
class Dist:
def_init_(self):
self, dist 1=0
self.dist 2=0
def read(self):
self.dist 1=int(input(“Enter distance 1”))
self.dist 2=int(input(“Enter distance 2”))
def disp(self):
print(“distance 1”, self.dist 1)
print(“distance 2”, self.dist 2)
def add(self):
print(“Total distances”, self.dist 1+self.dist 2)
def sub(self):
print(“Subtracted distance”, self.dist 1-self.dist 2)
d=Dist( )
choi = “y”
while(choi == “y”):
print(” 1. accept \n 2. Display \n 3. Total \n 4. Subtract”)
ch = int(input(“Enter your choice”))
if(ch==l):
d.read( )
elif(ch==2):
d.disp( )
elif(ch==3):
d.add( )
elif(ch==4):
d.sub( )
else:
print(“Invalid Input…”)
choi = input(“Do you want to continue”)
Output:

1. Accept
2. Display
3. Add
4. Subtract

Enter your choice : 3
Enter distance 1 : 100
Enter distance 2 : 75
Do you want to continue .. y

1. Accept
2. Display
3. Add
4. Subtract

Enter your choice : 3
Total distances : 175
Do you want to continue .. y

1. Accept
2. Display
3. Add
4. Subtract

Enter your choice : 2
Enter distance 1 : 100
Enter distance 2 : 75
Do you want to continue .. y

1. Accept
2. Display
3. Add
4. Sub

Enter your choice : 4
Subtracted distance : 25
Do you want to continue .. N

Samacheer kalvi 12th Computer Science Python Classes and Objects Additional Questions and Answers

PART – 1
1. Choose The Correct Answer

Question 1.
……………………. are also called as instances of a class or class variable.
Answer:
objects

Question 2.
All integer variables used in python program is an object of class ……………………….
Answer:
int

Question 3.
All the string variables are of object of class ……………………..
Answer:
strings

Question 4.
class is defined by the keyword ………………………
Answer:
class

Question 5.
A statement in a class definition may be a ………………………..
(a) variable declaration
(b) decision control
(c) loop
(d) all of these
Answer:
(d) all of these

Question 6.
………………….. and …………………. are called as members of the class
Answer:
class variables and methods

Question 7.
The first argument of the class method is ……………………….
(a) class
(b) func
(c) def
(d) self
Answer:
(d) self

Question 8.
The statements defined inside the class must be properly indented.
True / false
Answer:
True

Question 9.
The init function should begin and end with
(a) underscore
(b) double underscore
(c) #
(d) S
Answer:
(b) double underscore

Question 10.
…………………….. is used to initialize the class variables.
(a) constructor
(b) destructor
(c) class
(d) objects
Answer:
(a) constructor

Question 11.
Find the correct statement from the following.
(a) constructor function can be defined with arguments
(b) constructor function can be defined without arguments
(c) constructor function can be defined with or without argument
(d) constructor function cannot be defined
Answer:
(c) constructor function can be defined with or without argument

Question 12.
…………………….. is a special function to gets executed automatically when an object exit from the scope.
(a) constructor
(b) init
(c) destructor
(d) object
Answer:
(c) destructor

Question 13.
The variables which are defined inside the class is by default.
(a) private
(b) public
(c) protected
(d) local
Answer:
(b) public

Question 14.
Which variables can be accessed anywhere in the program using dot operator?
(a) private
(b) public
(c) protected
(d) auto
Answer:
(b) public

Question 15.
Which variables can be accessed only within the class?
(a) private
(b) public
(c) protected
(d) local
Answer:
(a) private

Question 16.
Match the following
1. constructor – (i) def process(self)
2. Destructor – (ii) S.x
3. method – (iii) _del_(self)
4. object – (iv) _init_(self, num)
(a) 1-(iv) 2-(iii) 3-(i) 4-(ii)
(b) 1-(i) 2-(ii) 3-(iii) 4-(iv)
(c) 1-(iv) 2-(ii) 3-(i) 4-(iii)
(d) 1-(i) 2-(iii) 3-(iv) 4-(ii)
Answer:
(a) 1-(iv) 2-(iii) 3-(i) 4-(ii)

PART – II
II. Answer The Following Questions

Question 1.
Write note on self?
Answer:
The class method must have the first argument named as self. No need to pass a value for this argument when we call the method. Python provides its value automatically. Even if – a method takes no arguments, it should be defined with the first argument called self. If a method is defined to accept only one argument it will take it as two arguments ie. self and the defined argument.

PART – III
III. Answer The Following Questions

Question 1.
Write the output for the program?
Answer:
class Sample:
def_init_(self, num):
print(“Constructor of class Sample…”)
self.num=num
print(“The value is num)
S=Sample(10)
Constructor of class sample…
The value is: 10

PART – IV
IV. Answer The Following Questions

Question 1.
Write a program to calculate area and circumference of a circle?
Answer:
class Circle:
pi=3.14
def_init_(self,radius):
self.radius=radius
def area(self):
return Circle.pi*(self.radius**2)
def circumference(self):
return 2*Circle.pi*self.radius
r = int(input(“Enter Radius:”))
C=Circle(r)
print(“The Area =”,C.area( ))
print(“The Circumference =”, C.circumference( ))
Output:
Enter Radius: 5
The Area = 78.5
The Circumference = 31.400000000000002

Question 2.
Write a menu driven program that keeps record of books available in your school library?
Answer:
class Library:
def_init_(self):
self.bookname=””
self.author=””
def getdata(self):
self.bookname = input(“Enter Name of the Book: “)
self.author = input(“Enter Author of the Book: “)
def display(self):
print(“Name of the Book: “,self.bookname)
print(” Author of the Book: “,self.author)
print(“\n”)
book=[ ] #empty list
ch = ‘y’
while(ch= =’y’):
print(“1. Add New Book \n 2.Display Books”)
resp = int(input(“Enter your choice :”))
if(resp= =1):
L=Library( )
L.getdata( )
book.append(L)
elif(resp= =2):
for x in book:
x.display( )
else:
print(“Invalid input….”)
ch = input(“Do you want continue….”)
Output:

1. Add New Book
2. Display Books

Enter your choice : 1
Enter Name of the Book: Programming in C++
Enter Author of the Book: K. Kannan
Do you want continue….y

1. Add New Book
2. Display Books

Enter your choice : 1
Enter Name of the Book: Learn Python
Enter Author of the Book: V.G.Ramakrishnan
Do you want continue….y

1. Add New Book
2. Display Books

Enter your choice : 1
Enter Name of the Book: Advanced Python
Enter Author of the Book: Dr. Vidhya
Do you want continue….y

1. Add New Book
2. Display Books Enter your choice : 1

Enter Name of the Book: Working with OpenOffice
Enter Author of the Book: N.V.Gowrisankar
Do you want continue….y

1. Add New Book
2. Display Books Enter your choice : 1

Enter Name of the Book: Data Structure
Enter Author of the Book: K.Lenin
Do you want continue….y

1. Add New Book
2. Display Books

Enter your choice : 1
Enter Name of the Book: An Introduction to Database System
Enter Author of the Book: R.Sreenivasan
Do you want continue….y

1. Add New Book
2. Display Books Enter your choice : 2

Enter Name of the Book: Programming in C++
Enter Author of the Book: K. Kannan
Name of the Book: Learn Python
Author of the Book: V.G.Ramakrishnan
Name of the Book: Advanced Python
Author of the Book: Dr. Vidhya
Name of the Book: Working with OpenOffice
Author of the Book: N.V.Gowrisankar
Name of the Book: Data Structure
Author of the Book: K.Lenin
Name of the Book: An Introduction to Database System
Author of the Book: R.Sreenivasan
Do you want continue….n

Students can Download Computer Science Chapter 4 Algorithmic Strategies Questions and Answers, Notes Pdf, Samacheer Kalvi 12th Computer Science Book Solutions Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 12th Computer Science Solutions Chapter 4 Algorithmic Strategies

Samacheer Kalvi 12th Computer Science Algorithmic Strategies Text Book Back Questions and Answers

PART – I
I. Choose The Best Answer

Question 1.
The word comes from the name of a Persian mathematician Abu Jafar Mohammed ibn – i Musa al Khowarizmi is called?
(a) Flow chart
(b) Flow
(c) Algorithm
(d) Syntax
Answer:
(c) Algorithm

Question 2.
From the following sorting algorithms which algorithm needs the minimum number of swaps?
(a) Bubble sort
(b) Quick sort
(c) Merge sort
(d) Selection sort
Answer:
(d) Selection sort

Question 3.
Two main measures for the efficiency of an algorithm are ……………………………
(a) Processor and memory
(b) Complexity and capacity
(c) Time and space
(d) Data and space
Answer:
(c) Time and space

Question 4.
The complexity of linear search algorithm is ……………………………
(a) O(n)
(b) O(log n)
(c) O(n2)
(d) O(n log n)
Answer:
(a) O(n)

Question 5.
From the following sorting algorithms which has the lowest worst case complexity?
(a) Bubble sort
(b) Quick sort
(c) Merge sort
(d) Selection sort
Answer:
(c) Merge sort

Question 6.
Which of the following is not a stable sorting algorithm?
(a) Insertion sort
(b) Selection sort
(c) Bubble sort
(d) Merge sort
Answer:
(b) Selection sort

Question 7.
Time complexity of bubble sort in best case is ……………………………
(a) θ(n)
(b) θ(n log n)
(c) θ(n2)
(d) θ(n(logn) 2)
Answer:
(a) θ(n)

Question 8.
The \(\Theta\) notation in asymptotic evaluation represents
(a) Base case
(b) Average case
(c) Worst case
(d) NULL case
Answer:
(b) Average case

Question 9.
If a problem can be broken into subproblems which are reused several times, the problem possesses which property?
Answer:
(a) Overlapping subproblems
(b) Optimal substructure
(c) Memoization
(d) Greedy
Answer:
(a) Overlapping subproblems

Question 10.
In dynamic programming, the technique of storing the previously calculated values is called?
(a) Saving value property
(b) Storing value property
(c) Memoization
(d) Mapping
Answer:
(c) Memoization

PART – II
II. Answer The Following Questions

Question 1.
What is an Algorithm?
Answer:
An algorithm is a finite set of instructions to accomplish a particular task. It is a step-by-step procedure for solving a given problem. An algorithm can be implemented in any suitable programming language.

Question 2.
Define Pseudo code?
Answer:

1. Pseudo code is a mix of programming – language – like constructs and Plain English.
2. Pseudo code is a notation similar to programming languages. Algorithms expressed in pseudo code are not intended to be executed by computers, but for communication among people.

Question 3.
Who is an Algorist?
Answer:

1. A person skilled in the design of algorithms are called as Algorist.
2. An algorithmic artist.

Question 4.
What is Sorting?
Answer:
Sorting is a method of arranging group of items in an ascending or descending order. Various sorting techniques in algorithms are Bubble Sort, Quick Sort, Heap Sort, Selection Sort, Insertion Sort.

Question 5.
What is searching? Write its types?
Answer:
A search algorithm is the step-by-step procedure used to locate specific data among a collection of data. Types of searching algorithms are

1. Linear search
2. Binary search
3. Hash search
4. Binary Tree search

PART – III
III. Answer The Following Questions

Question 1.
List the characteristics of an algorithm?
Answer:
Input, Output, Finiteness, Definiteness, Effectiveness, Correctness, Simplicity, Unambiguous, Feasibility, Portable and Independent.

Question 2.
Discuss about Algorithmic complexity and its types?
Answer:
The complexity of an algorithm f(n) gives the running time and/or the storage space required by the algorithm in terms of n as the size of input data.

Time Complexity:
The Time complexity of an algorithm is given by the number of steps taken by the algorithm to complete the process.

Space Complexity:
Space complexity of an algorithm is the amount of memory required to run to its completion.

Question 3.
What are the factors that influence time and space complexity?
Answer:
Time Complexity:
The Time complexity of an algorithm is given by the number of steps taken by the algorithm to complete the process.

Space Complexity:
Space complexity of an algorithm is the amount of memory required to run to its completion. The space required by an algorithm is equal to the sum of the following two components:

A fixed part is defined as the total space required to store certain data and variables for an algorithm. For example, simple variables and constants used in an algorithm. A variable part is defined as the total space required by variables, which sizes depends on the problem and its iteration. For example: recursion used to calculate factorial of a given value n.

Question 4.
Write a note on Asymptotic notation?
Answer:
Asymptotic Notations:
Asymptotic Notations are languages that uses meaningful statements about time and space complexity.

(I) Big O
Big O is often used to describe the worst – case of an algorithm.

(II) Big Ω
Big Omega is the reverse Big O, if Bi O is used to describe the upper bound (worst – case) of a asymptotic function, Big Omega is used to describe the lower bound (best-case).

(III) Big \(\Theta\)
When an algorithm has a complexity with lower bound = upper bound, say that an algorithm has a complexity O (n log n) and Ω (n log n), it’s actually has the complexity \(\Theta\) (n log n), which means the running time of that algorithm always falls in n log n in the best – case and worst – case.

Question 5.
What do you understand by Dynamic programming?
Answer:
Dynamic programming is an algorithmic design method that can be used when the solution to a problem can be viewed as the result of a sequence of decisions. Dynamic programming approach is similar to divide and conquer. The given problem is divided into smaller and yet smaller possible sub – problems.

PART – IV
IV. Answer The Following Questions

Question 1.
Explain the characteristics of an algorithm?
Answer:

1. Input – Zero or more quantities to be supplied.
2. Output – At least one quantity is produced.
3. Finiteness – Algorithms must terminate after finite number of steps.
4. Definiteness – All operations should be well defined. For example operations involving division by zero or taking square root for negative number are unacceptable.
5. Effectiveness – Every instruction must be carried out effectively.
6. Correctness – The algorithms should be error free.
7. Simplicity – Easy to implement.
8. Unambiguous – Algorithm should be clear and unambiguous. Each of its steps and their inputs/outputs should be clear and must lead to only one meaning.
9. Feasibility – Should be feasible with the available resources.
10. Portable – An algorithm should be generic, independent of any programming language or an operating system able to handle all range of inputs.
11. Independent – An algorithm should have step-by-step directions, which should be independent of any programming code.

Question 2.
Discuss about Linear search algorithm.?
Answer:
Linear Search:
Linear search also called sequential search is a sequential method for finding a particular value in a list. This method checks the search element with each element in sequence until the desired element is found or the list is exhausted. In this searching algorithm, list need not be ordered.

Pseudo code:
(I) Traverse the array using for loop
(II) In every iteration, compare the target search key value with the current value of the list.

1. If the values match, display the current index and value of the array
2. If the values do not match, move on to the next array element.

(III) If no match is found, display the search element not found.
To search the number 25 in the array given below, linear search will go step by step in a sequential order starting from the first element in the given array if the search element is found that index is returned otherwise the search is continued till the last index of the array. In this example number 25 is found at index number 3.

Example 1:
Input: values[ ] = {5, 34, 65, 12, 77, 35}
target = 77
Output: 4
Example 2:
Input: values[ ] = {101, 392, 1, 54, 32, 22, 90, 93}
target = 200
Output: -1 (not found)

Question 3.
What is Binary search? Discuss with example?
Answer:
Binary Search:
Binary search also called half – interval search algorithm. It finds the position of a search element within a sorted array. The binary search algorithm can be done as divide-and-conquer search algorithm and executes in logarithmic time.

Pseudo code for Binary search:
(I) Start with the middle element:

• If the search element is equal to the middle element of the array i.e., the middle value = number of elements in array/2, then return the index of the middle element.
• If not, then compare the middle element with the search value,
• If the search element is greater than the number in the middle index, then select the elements to the right side of the middle index, and go to Step-1.
• If the search element is less than the number in the middle index, then select the elements to the left side f the middle index, and start with Step-1.

(II) When a match is found, display success message with the index of the element matched.
(III) If no match is found for all comparisons, then display unsuccessful message.

Binary Search Working principles:
List of elements in an array must be sorted first for Binary search. The following example describes the step by step operation of binary search. Consider the following array of elements, the array is being sorted so it enables to do the binary search algorithm. Let us assume that the search element is 60 and we need to search the location or index of search element 60 using binary search.

First, we find index of middle element of the array by using this formula:
mid = low + (high – low) / 2
Here it is, 0 + (9 – 0 ) / 2 = 4 (fractional part ignored). So, 4 is the mid value of the array.

Now compare the search element with the value stored at mid value location 4. The value stored at location or index 4 is 50, which is not match with search element. As the search value 60 is greater than 50.

Now we change our low to mid + 1 and find the new mid value again using the formula, low to mid – 1
mid = low + (high – low) / 2
Our new mid is 7 now. We compare the value stored at location 7 with our target value 31.

The value stored at location or index 7 is not a match with search element, rather it is more than what we are looking for. So, the search element must be in the lower part from the current mid value location

The search element still not found. Hence, we calculated the mid again by using the formula.
high = mid – 1
mid = low + (high – low) / 2
Now the mid value is 5.

Now we compare the value stored at location 5 with our search element. We found that it is a match.

We can conclude that the search element 60 is found at location or index 5. For example if we take the search element as 95, For this value this binary search algorithm return unsuccessful result.

Question 4.
Explain the Bubble sort algorithm with example?
Answer:
Bubble sort algorithm:
Bubble sort is a simple sorting algorithm. The algorithm starts at the beginning of the list of values stored in an array. It compares each pair of adjacent elements and swaps them if they are in the unsorted order. This comparison and passed to be continued until no swaps are needed, which indicates that the list of values stored in an array is sorted. The algorithm is a comparison sort, is named for the way smaller elements “bubble” to the top of the list.

Although the algorithm is simple, it is too slow and less efficient when compared to insertion sort and other sorting methods. Assume list is an array of n elements. The swap function swaps the values of the given array elements.

Pseudo code:

1. Start with the fist element i.e., index = 0, compare the current element with the next element of the array.
2. If the current element is greater than the next element of the array, swap them.
3. If the current element is less than the next or right side of the element, move to the next element. Go to Step 1 and repeat until end of the index is reached.

Let’s consider an array with values {15, 11, 16, 12, 14, 13} Below, we have a pictorial representation of how bubble sort will sort the given array.

The above pictorial example is for iteration – 1. Similarly, remaining iteration can be done. The final iteration will give the sorted array.
At the end of all the iterations we will get the sorted values in an array as given below:

Question 5.
Explain the concept of Dynamic programming with suitable example?
Answer:
Dynamic programming:
Dynamic programming is an algorithmic design method that can be used when the solution to a problem can be viewed as the result of a sequence of decisions. Dynamic programming approach is similar to divide and conquer. The given problem is divided into smaller and yet smaller possible sub – problems.

Dynamic programming is used whenever problems can be divided into similar sub-problems, so that their results can be re-used to complete the process. Dynamic programming approaches are used to find the solution in optimized way. For every inner sub problem, dynamic algorithm will try to check the results of the previously solved sub-problems. The solutions of overlapped sub – problems are combined in order to get the better solution.

Steps to do Dynamic programming:

1. The given problem will be divided into smaller overlapping sub-problems.
2. An optimum solution for the given problem can be achieved by using result of smaller sub – problem.
3. Dynamic algorithms uses Memoization.

Fibonacci Series – An example:
Fibonacci series generates the subsequent number by adding two previous numbers. Fibonacci series starts from two numbers – Fib 0 & Fib 1. The initial values of fib 0 & fib 1 can be taken as 0 and 1.
Fibonacci series satisfies he following conditions:
Fibn = Fib_n-1 + Fib_n-2
Hence, a Fibonacci series for the n value 8 can look like this
Fib₈ = 0 1 1 2 3 5 8 13

Fibonacci Iterative Algorithm with Dynamic programming approach:
The following example shows a simple Dynamic programming approach for the generation of Fibonacci series.
Initialize f0 = 0, f1 = 1
step – 1: Print the initial values of Fibonacci f0 and f1
step – 2: Calculate fibanocci fib ← f0 + f1
step – 3: Assign f0 ← f1, f1 ← fib
step – 4: Print the next consecutive value of Fibonacci fib
step – 5: Go to step – 2 and repeat until the specified number of terms generated
For example if we generate fibonacci series up to 10 digits, the algorithm will generate the series as shown below:
The Fibonacci series is: 0 1 1 2 3 5 8 1 3 2 1 3 4 5 5

Samacheer kalvi 12th Computer Science Algorithmic Strategies Additional Questions and Answers

PART – I
I. Choose The Best Answer

Question 1.
Which one of the following is not a data structure?
(a) Array
(b) Structures
(c) List, tuples
(d) Database
Answer:
(d) Database

Question 2.
The word Algorithm has come to refer to a method ……………………………
(a) Solve a problem
(b) Insert a data
(c) Delete data
(d) Update data
Answer:
(a) Solve a problem

Question 3.
Which is wrong fact about the algorithm?
(a) It should be feasible
(b) Easy to implement
(c) It should be independent of any programming languages
(d) It should be generic
Answer:
(c) It should be independent of any programming languages

Question 4.
Complete the diagram

Answer:
Process

Question 5.
An algorithm that yields expected output for a valid input is called as ……………………………
Answer:
Algorithmic solution.

Question 6.
Program should be written for the selected language with specific ……………………………
Answer:
Syntax

Question 7.
…………………………… is an expression of algorithm in a programming language.
Answer:
Program

Question 8.
How many different phases are there in the analysis of algorithms and performance evaluations?
(a) 1
(b) 2
(c) 3
(d) Many
Answer:
(b) 2

Question 9.
Which one of the following is a theoretical performance analysis of an algorithm?
(a) A posteriori testing
(b) A priori estimates
(c) A preposition
(d) A post preori
Answer:
(b) A priori estimates

Question 10.
…………………………… is called performance measurement.
(a) A posteriori testing
(b) A priori estimates
(c) A preposition
(d) A post preori
Answer:
(a) A posteriori testing

Question 11.
Time is measured by counting the number of key operations like comparisons in the sorting algorithm. This is called as ……………………………
(a) Space Factor
(b) Key Factor
(c) Priori Factor
(d) Time Factor
Answer:
(d) Time Factor

Question 12.
Which of the following statement is true?
(a) Space Factor is the maximum memory space required by an algorithm
(b) Space Factor is the minimum memory spaces required by an algorithm
Answer:
(a) Space Factor is the maximum memory space required by an algorithm

Question 13.
In space complexity, the space required by an algorithm is equal to the sum of …………………………… part and …………………………… part.
Answer:
Fixed, Variable

Question 14.
…………………………… is an example for variable part of space complexity.
Answer:
Recursion

Question 15.
A …………………………… or …………………………… trade off is a way of solving in less time by using more storage space or by solving a given algorithm in very little space by spending more time.
Answer:
Space – timw, time – memory

Question 16.
Which is true related to the efficiency of an algorithm?
(I) Less time, more storage space
(II) More time, very little space
(a) I is correct
(b) II is correct
(c) Both are correct
(d) Both are wrong
Answer:
(c) Both are correct

Question 17.
How many asymptotic notations are used to represent time complexity of an algorithms?
(a) 1
(b) 2
(c) 3
(d) 4
Answer:
(c) 3

Question 18.
Which one of the following is not an Asymptotic notations?
(a) Big
(b) Big \(\Theta\)
(c) Big Ω
(d) Big ⊗
Answer:
(d) Big ⊗

Question 19.
………………………… is the reverse of Big O
(a) Big Ω
(b) Big \(\Theta\)
(c) Big C
(d) Big ⊗
Answer:
(a) Big Ω

Question 20.
………………………… describes the worst case of an algorithm.
(a) Big Q
(b) Big \(\Theta\)
(c) Big O
(d) Big C
Answer:
(c) Big O

Question 21.
…………………….. describes the lower bound of an algorithm.
(a) Big Ω
(b) Big \(\Theta\)
(c) Big O
(d) Big ⊗
Answer:
(a) Big Ω

Question 22.
Which search technique is also called sequential search techniques?
(a) Binary
(b) Binary Tree
(c) Hash
(d) Linear
Answer:
(d) Linear

Question 23.
What value will be returned by the linear search technique if value is not found?
(a) 0
(b) 1
(c) -1
(d) +1
Answer:
(c) -1

Question 24.
Which search algorithm is called as Half – Interval search algorithm?
(a) Binary
(b) Binary Tree
(c) Hash
(d) Linear
Answer:
(a) Binary

Question 25.
Which technique is followed by Binary Search algorithm?
(a) Subroutines
(b) Mapping
(c) Divide and conquer
(d) Namespaces
Answer:
(c) Divide and conquer

Question 26.
In Binary Search, if the search element is …………………….. to the middle element of the array, then index of the middle element is returned.
(a) >
(b) <
(c) =
(d) < >
Answer:
(c) =

Question 27.
In Binary search, if the search element is greater than the number in the middle index, then select the elements to the side of the middle index.
(a) Right
(b) Left
(c) Middle
(d) Bottom
Answer:
(a) Right

Question 28.
Fill in the box [Formula for Binary Search]
mid = low + (high – low) /
Answer:
2

Question 29.
……………………… is a simple sorting algorithm.
(a) Binary
(b) Bubble
(c) Selection
(d) Insertion
Answer:
(b) Bubble

Question 30.
Which one of the following is not a characteristics of Bubble Sort?
(a) Simple
(b) Too slow
(c) Too fast
(d) Less efficient
Answer:
(c) Too fast

Question 31.
In selection sort, there will be ……………………….. exchange for every pass through the list.
(a) 0
(b) 1
(c) 2
(d) 3
Answer:
(b) 1

Question 32.
How many number of passes are used in the Insertion Sort to get the final sorted list?
(a) 0
(b) 1
(c) n
(d) n -1
Answer:
(d) n – 1

Question 33.
………………………….. approach is similar to divide and conquer.
Answer:
Dynamic programming

Question 34.
………………………… is an example for dynamic programming approach.
(a) Fibonacci
(b) Prime
(c) Factorial
(d) Odd or Even
Answer:
(a) Fibonacci

Question 35.
Match the following.
(1) Linear search – (i) o(n²)
(2) Binary – (ii) o(n)
(3) Bubble Sort – (iii) o(log n)
(4) Merge Sort – (iv) o(n log n)
(a) 1 – (ii), 2 – (iii), 3 – (i), 4 – (iv)
(b) 1 – (i), 2 – (ii), 3 – (iii), 4 – (iv)
(c) 1 – (iv), 2 – (iii), 3 – (ii), 4 – (i)
(d) 1 – (iv), 2 – (ii), 3 – (i), 4 – (iii)
Answer:
(a) 1 – (ii), 2 – (iii), 3 – (i), 4 – (iv)

Question 36.
Time complexity of bubble sort in worst case is …………………………..
(a) θ(n)
(b) θ(n log n)
(c) θ(n2)
(d) θ(n(log n)2)
Answer:
(c) θ(n2)

Question 37.
The complexity of Merge Sort is …………………………
Answer:
o (n log n)

Question 38.
The complexity of Bubble Sort is …………………………
Answer:
o (n2)

Question 39.
The complexity of Binary search is ……………………….
Answer:
o (log n)

Question 40.
Pick the odd one out.
Merge Sort, Bubble, Binary, Insertion.
Answer:
Binary

PART – II
II. Answer The Following Questions

Question 1.
Define fixed part in the space complexity?
Answer:
A fixed part is defined as the total space required to store certain data and variables for an algorithm. For example, simple variables and constants used in an algorithm.

Question 2.
What is space – Time Trade off?
Answer:
A space – time or time – memory trade off is a way of solving in less time by using more storage space or by solving a given algorithm in very little space by spending more time.

PART – III
III. Answer The Following Questions

Question 1.
Design an algorithm to find square of the given number and display the result?
Answer:
Problem: Design an algorithm to find square of the given number and display the result. The algorithm can be written as:
Step 1 – start the process
Step 2 – get the input x
Step 3 – calculate the square by multiplying the input value ie., square ← x* x
Step 4 – display the result square
Step 5 – stop
Algorithm could be designed to get a solution of a given problem. A problem can be solved in many ways. Among many algorithms the optimistic one can be taken for implementation.

Question 2.
Differentiate Algorithm and Program?
Answer:
Algorithm:

1. Algorithm helps to solve a given problem logically and it can be contrasted with the program.
2. Algorithm can be categorized based on their implementation methods, design techniques etc.
3. There is no specific rules for algorithm writing but some guidelines should be followed.
4. Algorithm resembles a pseudo code which can be implemented in any language

Program:

1. Program is an expression of algorithm in a programming language.
2. Algorithm can be implemented by structured or object oriented programming approach.
3. Program should be written for the selected language with specific syntax
4. Program is more specific o a programming language

Question 3.
What are the two phases in the Analysis of algorithms and performance evaluation?
Answer:
Analysis of algorithms and performance evaluation can be divided into two different phases:
(a) A Priori estimates: This is a theoretical performance analysis of an algorithm. Efficiency of an algorithm is measured by assuming the external factors.
(b) A Posteriori testing: This is called performance measurement. In this analysis, actual statistics like running time and required for the algorithm executions are collected.

Question 4.
Name the factors where the program execution time depends on?
The program execution time depends on:

1. Speed of the machine
2. Compiler and other system Software tools
3. Operating System
4. Programming language used
5. Volume of data required

Question 5.
Write note on Big \(\Theta\)?
Answer:
Big \(\Theta\)
When an algorithm has a complexity with lower bound = upper bound, say that an algorithm has a complexity O (n log n) and Ω . (n log n), it’s actually has the complexity \(\Theta\) (n log n), which means the running time of that algorithm always falls in n log n in the best – case and worst – case.

PART – IV
IV. Answer The Following Questions

Question 1.
Explain Selection Sort?
Answer:
Selection sort
The selection sort is a simple sorting algorithm that improves on the performance of bubble sort by making only one exchange for every pass through the list. This algorithm will first find the smallest elements in array and swap it with the element in the first position of an array, then it will find the second smallest element and swap that element with the element in the second position, and it will continue until the entire array is sorted in respective order. This algorithm repeatedly selects the next-smallest element and swaps in into the right place for every pass. Hence it is called selection sort.

Pseudo code:
(I) Start from the first element (i.e.), index – 0, we search the smallest element in the array, and replace it with the element in the first position.

(II) Now we move on to the second element position, and look for smallest element present in the sub-array, from starting index to till the last index of sub – array.

(III) Now replace the second smallest identified in step-2 at the second position in the or original array, or also called first position in the sub array.

(IV) This is repeated, until the array is completely sorted.
Let’s consider an array with values {13, 16, 11, 18, 14, 15}
Below, we have a pictorial representation of how selection sort will sort the given array

In the first pass, the smallest element will be 11, so it will be placed at the first position. After that, next smallest element will be searched from an array. Now we will get 13 as the smallest, so it will be then placed at the second position.

Then leaving the first element, next smallest element will be searched, from the remaining elements. We will get 13 as the smallest, so it will be then placed at the second position. Then leaving 11 and 13 because they are at the correct position, we will search for the next smallest element from the rest of the elements and put it at third position and keep doing this until array is sorted.
Finally we will get the sorted array end of the pass as shown above diagram.

Question 2.
Explain Insertion Sort?
Answer:
Insertion Sort
Insertion sort is a simple sorting algorithm. It works by taking elements from the list one by one and inserting then in their correct position in to a new sorted list. This algorithm builds the final sorted array at the end. This algorithm uses n-1 number of passes to get the final sorted list as per the previous algorithm as we have discussed.
Pseudo for Insertion sort
Step 1 – If it is the first element, it is already sorted.
Step 2 – Pick next element
Step 3 – Compare with all elements in the sorted sub-list
Step 4 – Shift all the elements in the sorted sub-list that is greater than the value to be sorted
Step 5 – Insert the value
Step 6 – Repeat until list is sorted

At the end of the pass the insertion sort algorithm gives the sorted output in ascending order as shown below:

Students can Download Computer Applications Chapter 13 CSS – Cascading Style Sheets Questions and Answers, Notes Pdf, Samacheer Kalvi 11th Computer Applications Book Solutions Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 11th Computer Applications Solutions Chapter 13 CSS – Cascading Style Sheets

Samacheer Kalvi 11th Computer Applications CSS – Cascading Style Sheets Text Book Back Questions and Answers

I. Choose The Correct Answer

Question 1.
Expansion of CSS:
(a) Cascading Style Schools
(b) Cascading Style Scheme
(c) Cascading Style Sheets
(d) Cascading Style Shares
Answer:
(c) Cascading Style Sheets

Question 2.
Which of the following is the page level style?
(a) <Page>
(b) <Style>
(c) <Link>
(d) <H>
Answer:
(b) <Style>

Question 3.
CSS is also called as:
(a) Sitewide Style Sheets
(b) Internal Style Sheets
(c) Inline Style Sheets
(d) Internal Inline Sheets
Answer:
(a) Sitewide Style Sheets

Question 4.
The extension of CSS file is:
(a) .ssc
(b) .css
(c) .CSC
(d) .htm
Answer:
(b) .css

Question 5.
What is selector?
(a) Property
(b) Value
(c) HTML tag
(d) Name
Answer:
(c) HTML tag

Question 6.
The Declaration block of CSS is surrounded by:
(a) ( )
(b) [ ]
(c) { }
(d) <>
Answer:
(c) { }

Question 7.
The declaration should be terminated by:
(a) :
(b) ;
(c) .
(d) ,
Answer:
(b) ;

Question 8.
What is the property to set text as bold?
(a) Font-Style
(b) Font-Weight
(c) Font-Property
(d) Font-Bold
Answer:
(b) Font-Weight

Question 9.
Which of the following indicates that the text included is a comment?
(a) /**/
(b) !* *!
(c) <* *>
(d) \* *\
Answer:
(a) /**/

Question 10.
Which of the following ways below is correct, to write a CSS?
(a) p{coloured; text-align:center};
(b) p {colonred; text-align:center}
(c) p {color:red; text-align:center;}
(d) p (color:red;text-align:center;)
Answer:
(c) p {color:red; text-align:center;}

II. Answer To The Following Questions

Question 1.
What is the use of <style> tag?
Answer:
We are already know about the formatting tags and its attributes, in some situations, you may need to use a tag uniformly in the entire document. To do so, we can use <style> tag. A style tag is used to change the default characteristics of a particular tag in the entire web document wherever that tag is used.

Question 2.
What is CSS?
Answer:
Cascading Style Sheets (CSS) are also called as Sitewide Style sheets or external style. CSS is a style sheet language used for describing the formatting of a document written in HTML. Using CSS, you can control the font colour, font style, spacing between pages, columns size, border colour, background image or colour and various other effects in a web page.

Question 3.
Write the general format of linking CSS with HTML?
Answer:
The <link> tag is used to add CSS file with HTML in head section. While using <link> tag, the following attributes are also included along with standard values.
rel = “stylesheet”
type = “text/css”
The href attribute is used to link the .css file. General format of <Link> tag:
<Link rel = “stylesheet” type = “text/css” href = CSS_ File_Name_with_Extension>

Question 4.
What is Inline Style?
Answer:
“Inline style”, which is used to define style for a particular tag anywhere in an HTML document. You can define styles for any tag within an HTML document. But it is applicable only on that line where it is defined. If you use the same tag, again in the same documnet, it does not reflect the new style.

Question 5.
Write down general format of CSS declaration?
Answer:
The body of the style sheet consists of a series of rules.

Selector:
HTML Tag

Declaration:
{Properties: Values}

III. Answer To The Following Questions

Question 1.
What are the advantages of using CSS?
Answer:
Maintainability:
CSS are also defined and stored as separate files. So, the style and appearance of a web page can be dynamically changed and maintain with less effort.

Reusability:
The styles defined in CSS can be reused in multiple HTML pages.

Easy to understand:
The tags in web pages are well organized with style specifications and therefore it is easy to understand.

Question 2.
Write a short note on rule of CSS?
Answer:
CSS style declaration consists of two major parts; Selector and Declaration. The Selector refers an HTML tag in which you want to apply styles.

The Declaration is a block of code contains style definition. It should be surrounded by curly braces. You can include any number of properties for each selector, and they must be separated by semicolons, The property name and its value should be separated by a colon. Each declaration should be terminated by a semicolon (;).
Eg:

Question 3.
Wrie a CSS file to define text color and alignment to <p> tag?
Answer:
The style properties are defined to <p> tag. Hereafter, whenever you use the <p>, the contents will be displayed with modified properties.

If you want to use the above style definition as an internal style then it should be specified within <style>,</style> block in head section. If you want store the above definition for using all your web pages, you should save the above code as a separate file with extension.css

Question 4.
Write a CSS file to define font type, style and size to <h1> tag?
Answer:
<h1> tag in a particular font style and size with blue colour in the entire page,You can use <style> tag to define its properties in head section. The style of <h1> header tag is clearly defined. So, hereafter, the content between <h1> and </h1> will be displayed as per its definition.

IV. Answer To The Following Questions

Question 1.
Write an HTML document to display the following oaragraph as per the given description Using CSS:
Font Name:
Cooper Black

Style:
Bold Italics

Color:
Blue “The State Institute of Education (SIE) was established in 1965 to provide for systematic study of problems relating to School Education under the administration of Directorate of School Education.”

Question 2.
List and explain the Font and text element properties and values used CSS?
Answer:

Samacheer Kalvi 11th Computer Applications HTML – Adding Multimedia Elements and Forms Additional Questions and Answers

I. Choose The Correct Answer

Question 1.
Which tag is used to change the default characteristics of web document?
(a) Style
(b) Font
(c) Text
(d) Colour
Answer:
(a) Style

Question 2.
Which is used to define style for a particular tag anywhere in a HTML document?
(a) Internal style
(b) Inline style
(c) External style
(d) Page style
Answer:
(b) Inline style

Question 3.
CSS was invented by:
(a) Hakon Wium Lie
(b) Hakon Willium Lee
(c) Hakon Street Man
(d) Hakon Lee
Answer:
(a) Hakon Wium Lie

Question 4.
The <style> tag are also called as:
(a) page-level styles
(b) inline styles
(c) external styles
(d) both (a) & (c)
Answer:
(a) page-level styles

Question 5.
Which section is used by the <link> tag to add CSS file?
(a) Body
(b) Head
(c) Style
(d) Title
Answer:
(b) Head

Question 6.
Expand XHTML:
(a) Extensible Hypertext Markup Language
(b) Extended Hypertext Markup Language
(c) Executed Hypertext Markup Language
(d) Except Hypertext Markup Language
Answer:
(a) Extensible Hypertext Markup Language

II. Answer The Following Questions

Question 1.
What is called page-level sheets or internal sheets?
Answer:
The <style> tag controls the presentation styles of a particular HTML document. If you want to use a particular tag with the same style applied in one HTML document to another is not possible. Thus, the <style> tags are called as “Page-Level Styles” or “Internal Style sheets”.

Question 2.
What is known as sitewide style sheets or external style sheets?
Answer:
The “Internal Style Sheet” is defined and implemented only within an HTML document. If you want use the same style to multiple pages, you should define styles as a separate style file. These separate style files are known as “Sitewide Style Sheets” or ‘”External Style Sheets”.

III. Answer The Following Questions

Question 1.
Write the suitable example for creating CSS style?
Answer:
P {
font-style : Italic;
color :MediumSeaGreen;
}
H1
{
border: 2px solid red;
}
The above code should be saved with extension. css

Question 2.
Write the properties and values of paragraph margin in CSS?
Answer:

IV. Answer The Following Questions

Question 1.
Write the html code to change the background colour of browser using CSS?
Answer:
– Back_Color.css —
body
{
background-color : pink;
}
Background_CSS.htm
<html>
<head>
<title> Changing Background using CSS </title>
<link rel = “stylesheet” type=”text/css” href=”Body_Color.css”> </head>
<body>
<H1> Welcome to CSS
</H1>
</body>
</html>

Students can Download Computer Science Chapter 7 Python Functions Questions and Answers, Notes Pdf, Samacheer Kalvi 12th Computer Science Book Solutions Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 12th Computer Science Solutions Chapter 7 Python Functions

Samacheer Kalvi 12th Computer Science Python Functions Text Book Back Questions and Answers

PART – I
I. Choose The Best Answer

Question 1.
A named blocks of code that are designed to do one specific job is called as …………………………
(a) Loop
(b) Branching
(c) Function
(d) Block
Answer:
(c) Function

Question 2.
A Function which calls itself is called as …………………………
(a) Built – in
(b) Recursion
(c) Lambda
(d) Return
Answer:
(b) Recursion

Question 3.
Which function is called anonymous un – named function?
(a) Lambda
(b) Recursion
(c) Function
(d) Define
Answer:
(a) Lambda

Question 4.
Which of the following keyword is used to begin the function block?
(a) Define
(b) For
(c) Finally
(d) Def
Answer:
(d) Def

Question 5.
Which of the following keyword is used to exit a function block?
(a) Define
(b) Return
(c) Finally
(d) Def
Answer:
(b) Return

Question 6.
While defining a function which of the following symbol is used.
(a) ; (semicolon)
(b) . (dot)
(c) : (colon)
(d) $ (dollar)
Answer:
(c) : (colon)

Question 7.
In which arguments the correct positional order is passed to a function?
(a) Required
(b) Keyword
(c) Default
(d) Variable – length
Answer:
(a) Required

Question 8.
Read the following statement and choose the correct statement(s).
(I) In Python, you don’t have to mention the specific data types while defining function.
(II) Python keywords can be used as function name.

(a) (I) is correct and (II) is wrong
(b) Both are correct
(c) (I) is wrong and (II) is correct
(d) Both are wrong
Answer:
(a) (I) is correct and (II) is wrong

Question 9.
Pick the correct one to execute the given statement successfully.
if_: print (x,” is a leap year”)
(a) x % 2 = 0
(b) x % 4 = = 0
(c) x / 4 = 0
(d) x % 4 = 0
Answer:
(b) x % 4 = = 0

Question 10.
Which of the following keyword is used to define the function testpython():?
(a) Define
(b) Pass
(c) Def
(d) While
Answer:
(c) Def

PART – II
II. Answer The Following Questions

Question 1.
What is function?
Answer:
Functions are named blocks of code that are designed to do specific job. If you need to perform that task multiple times throughout your program, you just call the function dedicated to handling that task.

Question 2.
Write the different types of function?
Answer:

1. User – defined Functions
2. Built – in Functions
3. Lambda Functions
4. Recursion Functions

Question 3.
What are the main advantages of function?
Answer:
Main advantages of functions are:

1. It avoids repetition and makes high degree of code reusing.
2. It provides better modularity for your application.

Question 4.
What is meant by scope of variable? Mention its types?
Answer:
Scope of variable refers to the part of the program, where it is accessible, i.e., area where you can refer (use) it. We can say that scope holds the current set of variables and their values. The two types of scopes are: local scope and global scope.

Question 5.
Define global scope?
Answer:
A variable, with global scope can be used anywhere in the program. It can be created by defining a variable outside the scope of any function/block.

Question 6.
What is base condition in recursive function?
Answer:
The condition that is applied in any recursive function is known as base condition. A base condition is must in every recursive function otherwise it will continue to execute like an infinite loop.

Question 7.
How to set the limit for recursive function? Give an example?
Answer:
Python also allows you to change the limit using sys.setrecursionlimit (limit value).
Example:
import sys
sys.setrecursionlimit(3000)
def fact (n):
if n = = 0:
return 1
else:
return n * fact (n – 1)
print (fact (2000))

PART – III
III. Answer The Following Questions

Question 1.
Write the rules of local variable?
Answer:
Rules of local variable:

1. A variable with local scope can be accessed only within the function/block that it is created in.
2. When a variable is created inside the function/block, the variable becomes local to it.
3. A local variable only exists while the function is executing.
4. The formate arguments are also local to function.

Question 2.
Write the basic rules for global keyword in python?
Answer:
The basic rules for global keyword in Python are:

1. When we define a variable outside a function, it’s global by default. You don’t have to use global keyword.
2. We use global keyword to read and write a global variable inside a function.
3. Use of global keyword outside a function has no effect

Question 3.
What happens when we modify global variable inside the function?
Answer:
It will change the global variable value outside the function also.

Question 4.
Differentiate ceil ( ) and floor ( ) function?
Answer:

Question 5.
Write a Python code to check whether a given year is leap year or not?
Leap year or not:
Program code:
Answer:
n = int (input(“Enter any year”))
if (n % 4 = = 0):
print “Leap year”
else:
print “Not a Leap year”
Output:
Enter any year 2001
Not a Leap year

Question 6.
What is composition in functions?
Answer:
The value returned by a function may be used as an argument for another function in a nested manner. This is called composition. For example, if we wish to take a numeric value or an expression as a input from the user, we take the input string from the user using the function input ( ) and apply eval ( ) function to evaluate its value.

Question 7.
How recursive function works?
Answer:

1. Recursive function is called by some external code.
2. If the base condition is met then the program gives meaningful output and exits.
3. Otherwise, function does some required processing and then calls itself to continue recursion.

Question 8.
What are the points to be noted while defining a function?
Answer:

1. Function blocks begin with the keyword “def ” followed by function name and parenthesis ( ).
2. Any input parameters or arguments should be placed within these parentheses when you define a function.
3. The code block always comes after a colon (:) and is indented.
4. The statement “return [expression]” exits a function, optionally passing back an expression to the caller. A “return” with no arguments is the same as return None

PART – IV
IV. Answer The Following Questions

Question 1.
Explain the different types of function with an example?
Answer:
Types of Functions:
Basically, we can divide functions into the following types:

1. User – defined Functions
2. Built – in Functions
3. Lambda Functions
4. Recursion Functions

Functions:
User – defined functions
Built – in functions
Lambda functions
Recursion functions

Description:
Functions defined by the users themselves.
Functions that are inbuilt with in Python.
Functions that are anonymous un-named function.
Functions that calls itself is known as recursive.

(I) Syntax for User defined function
def <function_name ( [parameter1, parameter!…] ) > :
<Block of Statements> return <expression /None>
Example:
def hello ( ):
print (“hello – Python”)
return

Advantages of User – defined Functions:

1. Functions help us to divide a program into modules. This makes the code easier to manage.
2. It implements code reuse. Every time you need to execute a sequence of statements, all you need to do is to call the function.
3. Functions, allows us to change functionality easily, and different programmers can work on different functions.

(II) Anonymous Functions:
In Python, anonymous function is a function that is defined without a name. While normal functions are defined using the def keyword, in Python anonymous functions are defined using the lambda keyword. Hence, anonymous functions are also called as lambda functions.

The use of lambda or anonymous function:

1. Lambda function is mostly used for creating small and one-time anonymous function.
2. Lambda functions are mainly used in combination with the functions like filter ( ), map ( ) and reduce ( ).

Syntax of Anonymous Functions
The syntax for anonymous functions is as follows:
lambda [argument(s)] expression
Example:
sum = lambda argl, arg2: argl + arg2
print (‘The Sum is sum (30, 40))
print (‘The Sum is :’, sum (-30, 40))
Output:
The Sum is: 70
The Sum is: 10
The above lambda function that adds argument argl with argument arg2 and stores the result in the variable sum. The result is displayed using the print ( ).

(III) Functions using libraries:
Built – in and Mathematical functions

(IV) Recursive functions:
When a function calls itself is known as recursion. Recursion works like loop but sometimes 1 ’ it makes more sense to use recursion than loop. You can convert any loop to recursion.
Example:
def fact(n):
if n = = 0:
return 1
else:
return n * fact (n – 1)
print (fact (0))
print (fact (5))
Output:
1
120

Question 2.
Explain the scope of variables with an example?
Answer:
Scope of Variables:
Scope of variable refers to the part of the program, where it is accessible, i.e., area where you can refer (use) it. We can say that scope holds the current set of variables and their values.
The two types of scopes are local scope and global scope.

(I) Local scope:
A variable declared inside the function’s body or in the local scope is called as local variable.

Rules of local variable:

1. A variable with local scope can be accessed only within the function/block that it is created in.
2. When a variable is created inside the function/block; the variable becomes local to it.
3. A local variable only exists while the function is executing.
4. The formate arguments are also local to function.

Example: Create a Local Variable
def loc ( ):
y = 0 # local scope
print (y)
loc ( )
Output:
0
(II) Global Scope:
A variable, with global scope can be used anywhere in the program. It can be created by defining a variable outside the scope of any function/block.

Rules of global Keyword:
The basic rules for global keyword in Python are:

1. When we define a variable outside a function, it’s global by default. You don’t have to useglobal keyword.
2. We use global keyword to read and write a global variable inside a function.
3. Use of global keyword outside a function has no effect

Example: Global variable and Local variable with same name
x = 5 def loc ( ):
x = 10
print (“local x:”, x)
loc ( )
print (“global x:”, x)
Output:
local x: 10
global x: 5
In above code, we used same name ‘x’ for both global variable and local variable. We get different result when we print same variable because the variable is declared in both scopes, i.e. the local scope inside the function loc() and global scope outside the function loc ( ).
The output:- local x: 10, is called local scope of variable.
The output: – global x: 5, is called global scope of variable.

Question 3.
Explain the following built-in functions?
(a) id ( )
(b) chr ( )
(c) round ( )
(d) type ( )
(e) pow ( )
Answer:

Question 4.
Write a Python code to find the L.C.M. of two numbers?
Answer:
Method I using functions:
def lcm (x, y):
if x > y:
greater = x
else:
greater = y while (true):
if ((greater % x = = 0) and (greater % y = = 0)):
lcm = greater break
greater + = 1
return lcm
num 1 = int (input(“Enter first number : “))
num 2 = int (input(“Enter second number : “))
print (“The L.C.M of”, numl, “and”, num, “is”, lcm(num1, num2))

Method II
(without using functions)
a = int (input (“Enter the first number :”))
b = int (input (“Enter the second number :”))
if a > b:
mini = a
else:
min 1 = b
while(1):
if (min 1 % a = = 0 and mini 1 % b = = 0):
print (“LCM is:”, mini)
break
mini = min 1 + 1
Output:
Enter the first number: 15
Enter the second number: 20
LCM is: 60

Question 5.
Explain recursive function with an example?
Answer:
Python recursive functions
When a function calls itself is known as recursion. Recursion works like loop but sometimes it makes more sense to use recursion than loop. You can convert any loop to recursion.
A recursive function calls itself. Imagine a process would iterate indefinitely if not stopped by some condition! Such a process is known as infinite iteration. The condition that is applied in any recursive function is known as base condition. A base condition is must in every recursive function otherwise it will continue to execute like an infinite loop.

Working Principle:

1. Recursive function is called by some external code.
2. If the base condition is met then the program gives meaningful output and exits.
3. Otherwise, function does some required processing and then calls itself to continue recursion. Here is an example of recursive function used to calculate factorial.

Example:
def fact (n):
if n = = 0:
return 1
else:
return n * fact (n – 1)
print (fact (0))
print (fact (5))
Output:
1
120

Practice Programs

Question 1.
Try the following code in the above program?
Answer:

Output:
1. Error

2. Name: Sri
Salary: 3500
Salary: 3500

3. Name: Balu
Salary: 3500

4. Name: Jose
Salary: 1234

5. Name:
Salary: 1234

Question 2.
Evaluate the following functions and write the output?
Answer:

Output:

1. 30
2. 9
3. 8
4. 9

Question 3.
Evaluate the following functions and write the output?
Answer:


Output:
(i) 1. 13
2. 3.2

(ii) 1. 50
2. 36

(iii) <class ‘str’>

(iv) 0b10000

(v). 1. CR (carriage return)
2. It moves the cursor to the beginning of same line

(vi) 1. 8.2
2. 18.0
3. 0.510
4. 0.512

(vii) 1. B
2. a
3. A
4. 6
5. 10

(viii) 1. 0.125
2. 8.0
3. 1

Samacheer kalvi 12th Computer Science Python Functions Additional Questions and Answers

PART – 1
I. Choose The Best Answer

Question 1.
Name of the function is followed by ………………………….
(a) ( )
(b) [ ]
(c) <>
(d) { }
Answer:
(a) ( )

Question 2.
A …………………………. is one or more lines of code, grouped together.
(a) Code –
(b) Block
(c) Function
(d) Arguments
Answer:
(b) Block

Question 3.
A block of code begins when a line is indented by ……………………. spaces usually.
(a) 2
(b) 3
(c) 4
(d) 5
Answer:
(c) 4

Question 4.
A block within a block is called …………………………… block.
Answer:
Nested

Question 5.
If the return has no argument, …………………………….. will be displayed as the last statement of the output.
(a) No
(b) None
(c) Nothing
(d) No value
Answer:
(b) None

Question 6.
How many types of functions arguments are there?
(a) 2
(b) 3
(c) 4
(d) 5
Answer:
(c) 4

Question 7.
The arguments can be given in improper order in ………………………. arguments.
(a) Required
(b) Keyword
(c) Default
(d) Variable – length
Answer:
(b) Keyword

Question 8.
What is the symbol used to denote variable – length arguments?
(a) +
(b) *
(c) &
(d) ++
Answer:
(b) *

Question 9.
How many methods of arguments passing are there in variable length method.
(a) 2
(b) 3
(c) 4
(d) 5
Answer:
(a) 2

Question 10.
Non – keyword variable arguments are called ……………………………….
Answer:
Tuples

Question 11.
In python’s ……………………….. function supports variable length arguments.
(a) Input
(b) Write
(c) Output
(d) Print
Answer:
(d) Print

Question 12.
Lambda functions cannot be used in combination with ………………………….
(a) Filter
(b) Map
(c) Print
(d) Reduce
Answer:
(c) Print

Question 13.
Lambda function can only access ……………………….. variables.
(a) Local
(b) Function
(c) Global
(d) Nested
Answer:
(c) Global

Question 14.
How many types of scopes are there?
(a) 2
(b) 3
(c) 4
(d) 5
Answer:
(a) 2

Question 15.
Find the correct one:
(a) Global keyword outside the function has no effect
(b) Global keyword outside the function has effect
Answer:
(a) Global keyword outside the function has no effect

Question 16.
Read the following statement and choose the wrong statements
(a) Without using the global keyword, we cannot modify the global variable
(b) Using global keyword we can modify the global variable
(c) Without global keyword, we can modify the global variable
Answer:
(c) Without global keyword, we can modify the global variable

Question 17.
Find the correct statement.
(a) Local and global variables cannot be used in the same code
(b) Local and global variables can be used in the same code
Answer:
(b) Local and global variables can be used in the same code

Question 18.
The ……………………… function is the inverse of chr ( ) function.
(a) Ord ( )
(b) Abs ( )
(c) Chr ( )
(d) Bin ( )
Answer:
(a) Ord ( )

Question 19.
…………………………. function is the alternative for bin ( ) function.
(a) Ord ( )
(b) Format ( )
(c) Binary ( )
(d) Ord ( )
Answer:
(b) Format ( )

Question 20.
bin ( ) returns the binary string prefixed with ………………………… for the given integer number
(a) b
(b) ob
(c) obin
(d) bin
Answer:
(b) ob

Question 21.
Find the output.
d = 43
print(‘A =ord(d))
(a) 67
(b) 95
(c) 97
(d) 65
Answer:
(d) 65

Question 22.
Find the output,
d = 43
print (chr(d))
(a) –
(b) +
(c) *
(d) /
Answer:
(b) +

Question 23.
The default precision for fixed point number is ………………………….
(a) 2
(b) 4
(c) 6
(d) 8
Answer:
(c) 6

Question 24.
How many formats are there for the format ( ) functions?
(a) 12
(b) 5
(c) 3
(d) 1
Answer:
(c) 3

Question 25.
………………………. function returns the smallest integer greater than or equal to x
(a) Sqrt
(b) Flow
(c) Floor
(d) Cell
Answer:
(d) Cell

Question 26.
………………………. function is used to evaluate the input value.
(a) Input
(b) Valuate
(c) Eval
(d) Val
Answer:
(c) Eval

Question 27.
Any Loop can be converted to recursive functions.
True / False
Answer:
True

Question 28.
Find true statement
(a) Recursive function call itself
(b) Recursive function have to be called externally
Answer:
(a) Recursive function call itself

PART – II
II. Answer The Following Questions.

Question 1.
Define nested blocks?
Answer:
Nested Block:
A block within a block is called nested block. When the first block statement is indented by a single tab space, the second block of statement is indented by double tab spaces.

Question 2.
Give the syntax for passing parameters in functions?
Answer:
Parameters or arguments can be passed to functions
def function _ name (parameter (s) separated by comma):

Question 3.
Differentiate parameters and arguments?
Answer:
Parameters are the variables used in the function definition whereas arguments are the values we pass to the function parameters.

Question 4.
Classify Function Arguments?
Function Arguments:

1. Required arguments
2. Keyword arguments
3. Default arguments
4. Variable – length arguments

Question 5.
Define default arguments?
Answer:
Default Arguments
In Python the default argument is an argument that takes a default value if no value is provided in the function call. The following example uses default arguments, that prints default salary when no argument is passed, def printinfo(sal=3500):

Question 6.
What are the two methods of passing arguments in variable length arguments?
Answer:
In Variable Length arguments we can pass the arguments using two methods.

1. Non keyword variable arguments
2. Keyword variable arguments

PART – III
III. Answer The Following Questions.

Question 1.
Write the output for the program given below?
Answer:
Program:
def printdata (name, age):
print (“Example – 3 Keyword arguments”)
print (“Name :”,name)
print (“Age age)
return
# Now you can call printdata ( ) function
printdata (age = 25, name = “Gshan”)
Output:
Example – 3 Keyword arguments
Name: Gshan
Age: 25

Question 2.
Give the syntax for defining variable – length arguments.?
Syntax – Variable – Length Arguments:
Answer:
def function _name (*args):
function_body
return_statement

Question 3.
Write note on return statement?
Answer:
The return Statement
1. The return statement causes your function to exit and returns a value to its caller. The point of functions in general is to take inputs and return something.

2. The return statement is used when a function is ready to return a value to its caller. So, only one return statement is executed at run time even though the function contains multiple return statements.

3. Any number of ‘return’ statements are allowed in a function definition but only one of them is executed at run time.

Question 4.
Find the output?
Answer:
Program:
Answer:
x = 0 # global variable
def add ( ):
global x
x = x + 5 # increment by 2
print (“Inside add ( ) function x value is:”, x)
add ( )
print (“In main x value is x)
Output:
Inside add ( ) function x value is: 5.
In main x value is: 5

Question 5.
Write note on format function?
Answer:

PART – IV
IV. Answer The Following Questions.

Question 1.
Write any 5 built in functions?
Answer: