Category: Class 10

Looking to improve English skills and gain more subject knowledge then the best resources that you can use here is Samacheer Kalvi 10th English Solutions for Grammar Active And Passive Voice Questions and Answers.

In the Samacheer Kalvi 10th English Guide for textbook solutions, subject experts covered all types of questions and answers related to the topics, quick notes, summary, solved & unsolved exercises, etc. If you are planning to prepare Chapter via textbook, then you’re suggested to go with this Samacheer Kalvi 10th English Book Solutions Questions and Answers PDF for better understanding and preparation.

Tamilnadu Samacheer Kalvi 10th English Grammar Active And Passive Voice

English Subject experts who are having max years of experience prepared this Tamilnadu State Board Solutions for 10th English Grammar Active And Passive Voice Questions and Answers. They have explained all the topics covered in the board prescribed latest syllabus in a simple way to understand easily. So, students can prepare English from this Samacheer Kalvi 10th English Book Questions and Answers PDF. Download the Tamilnadu State Board 10th English Workbook Answers PDF by accessing the below links and learn properly for the final exams to score well.

There are two ways of expressing an action by using a transitive verb.
Read the following sentences:

1. Magesh killed a rat.
2. A rat was killed by Magesh..

These two sentences have the same meaning. These are simply two different ways of saying the same thing. There is, however, a shift in stress on the agent and also a change in the form of verb. In sentence (i), the subject ‘Magesh ‘ is the ‘doer of the action. It acts or is active. So the verb ‘killed’ is in active voice.

In sentence (ii), the subject ‘A rat’ is the ‘receiver’ of action. It suffers the action done by someone else (Magesh, in this case). It is acted upon. So the verb ‘was killed’ is in passive voice.

A. Rewrite the following sentences using passive voice:
1. This mango tastes sweet.
This mango is sweet when tasted.

2. The rose smells sweet.
The rose is sweet when smelt.

3. Grass grows over the fields.
The fields are overgrown with grass.

4. It is time to ring the bell.
It is time for the bell to be rung.

5. This bottle contains milk.
Milk is contained in this bottle.

6. One must do one’s duty.
Duty must be done.

7. Your shirt needs washing.
Your shirt needs to be washed.

8. She accused him of theft.
He was accused of theft by her.

9. She might win the match.
The match might be won by her.

10. How will you cross the river?
How will the river be crossed by you?

11. When did you write the letter?
When was the letter written by you?

12. Have you taught the boy?
Has the boy been taught by you?

13. Why did she beat the servant?
Why was the servant beaten by her?

14. Where will you spend your holidays?
Where will your holidays be spent by you?

15. Light the lamp.
Let the lamp be lighted.

16. People harvest water during the rainy season.
Water is harvested by people during the rainy season.

17. Rekha has forgotten the answer to the first question. She is answering the last question now.
The answer to the first question has been forgotten by Rekha. Now, the last question is being answered by her.

18. He does not obey his teachers.
His teachers are not obeyed by him.

19. I shall help him.
He will be helped by me.

20. You will not disturb me.
I shall not be disturbed by you.

B. Rewrite the following sentences using active voice:
I. By whom are you taught Physics?
Who teaches you Physics?

2. What was bought by her?
What did she buy?

3. By whom will the bill be paid?
Who will pay the bill?

4. A letter was being written by him.
He was writing a letter.

5. My work was not being done by me.
I was not doing my work.

6. Was hockey being played by the children?
Were the children playing hockey?

7. The food had already been cooked by her.
She had already cooked the food.

8. By whose team had the match been won?
Whose team had won the match?

9. You are requested to post this letter.
Please post this letter.

10. You are advised to work hard.
Work hard.

11. Was the window broken by him?
Did he break the window?

12. What is wanted by you?
What do you want?

13. The match might be won by her.
She might win the match.

14. My proposal was objected to by her.
She objected to my proposal.

15. His request was acceded to by us.
We acceded to his request.

16. It is said that he is a rich man.
People say that he is a rich man.

17. I am surprised at your behavior.
Your behavior surprises me.

18. Milk is contained in this bottle.
This bottle contains milk.

19. Is French spoken by them?
Do they speak French?

20. From where was this pen bought by you?
Where did you buy this pen from?

We hope the data given here will benefit you to the fullest extent at the time of preparation. For better understanding of English subject this Samacheer Kalvi 10th English Answers for Class 10th English Grammar Active And Passive Voice PDF is the best resource. Download & ace up your preparation. Keep in touch with us and get the latest information on Tamilnadu State board Textbook Answers PDF.

Looking to improve English skills and gain more subject knowledge then the best resources that you can use here is Samacheer Kalvi 10th English Solutions for Grammar Do As Directed Transformation and Synthesis Questions and Answers.

In the Samacheer Kalvi 10th English Guide for textbook solutions, subject experts covered all types of questions and answers related to the topics, quick notes, summary, solved & unsolved exercises, etc. If you are planning to prepare Chapter via textbook, then you’re suggested to go with this Samacheer Kalvi 10th English Book Solutions Questions and Answers PDF for better understanding and preparation.

Tamilnadu Samacheer Kalvi 10th English Grammar Do As Directed: Transformation and Synthesis

English Subject experts who are having max years of experience prepared this Tamilnadu State Board Solutions for 10th English Grammar Do As Directed Transformation and Synthesis Questions and Answers. They have explained all the topics covered in the board prescribed latest syllabus in a simple way to understand easily. So, students can prepare English from this Samacheer Kalvi 10th English Book Questions and Answers PDF. Download the Tamilnadu State Board 10th English Workbook Answers PDF by accessing the below links and learn properly for the final exams to score well.

Reported Speech/Direct And Indirect Speech
A. Write what the people actually said:

1. Neela advised her friend not to go too near the lion’s cage.
Neela told her friend, “Don’t go very near the lion’s cage”.

2. Anu asked Ajith when the film was going to begin.
Anu said to Ajith, “When is the film going to begin?”.

3. Dhoni exclaimed that it was an amazing performance by Indian test Cricket team.
Dhoni said, “What an amazing performance by Indian test cricket team!”.

4. Ajay exclaimed that the Tajmahal was a wonderful monument.
Ajay said, “What a wonderful monument Tajmahal is!”

5. The conservator of museum said to the tourists that they should not deface the monuments.
The conservator of museum said to the tourists, “You should not deface the monuments”.

6. Gopinath told Sindhu that he would support her at any cost.
Gopinath said to Sindhu, “I will support you at any cost”.

7. Mom advised her daughter not to waste water.
Mom said to her daughter, “Don’t waste water”.

8. The teacher said that opportunities seldom knock twice.
The teacher said, “Opportunities seldom knock twice”.

9. The talking doll asked him whether he knew the secret of life.
The talking doll said to him, “Do you know the secret of life”?

10. Kavin told his grandmother that he would help her to change her glasses.
Kavin said to his grandmother, “I will help you to change your glasses”.

11. The doctor asked Kama if he had got the tests done.
Doctor asked Kama, “Have you got the tests done?”.

12. Reema asked Yogesh how he was.
Reema said to Yogesh, “Hi Yash! How are you?”

13. Malini asked Hari where he was yesterday.
Malini said to Hari, “Where were you yesterday?”

14. Ankit told the teacher that he had caught a fever the previous day.
Ankit said, “Ma’am yesterday I caught a fever.”

15. Ram exclaimed that he is really excited to be in Thanjavur.
Ram said, “I am really excited to be in Thanjavur.”

B. Report the actual words of the speaker:

1. Karthick told his parents, “I want to pursue agriculture”.
Karthick told his parents that he wanted to pursue agriculture.

2. Prabu said to Soundar, “Can you please lend me your Math note book for copying?” Prabu requested Soundar whether (if) he could lend his Math note book for copying.

3. The passenger told the conductor, “Hey, you are standing on my toes”.
The passenger shouted at the .conductor that he was standing on his toes.

4. Minister said to the security officer, “Send away the contractor from here right now.”
Minister ordered the security officer to send away the contractor from there right then.

5. The teacher said to Radha, “can you give a reason for your poor marks in math?”
The teacher asked Radha whether in Math she could give a reason for poor marks.

6. Guru said to Mukhil, “I have completed my assignment. I need to take rest for some time”.
Guru told Mukhil that he had completed his assignment and he needed to take rest for some time.

7. Praveen said, “I don’t go to movies often, and my mother wifi not allows it”.
Praveen, said that he does not go to movies often and his mother would not allow that.

8. “What a beautiful view it is!” said my friend.
My friend exclaimed that it was a very beautiful view.

9. The blind lady said to the student, “please help me cross the road”.
The blind lady requested the student to help her cross the road.

10. The teacher said to the boy, “I have often warned you to concentrate on your studies”.
The teacher told the boy that he had often warned him to concentrate on his studies.

11. Nathen said to his mother, “I could not call my English tutor.”
Nathen told his mother that he could not call his English tutor.

12. Servant said to the master, “Give me my salary”.
The servant asked the master to give him his salary.

13. Husband said to the Doctor, “Doctor, what will the total expenses be In the end?”
The husband asked the doctor what the total expenses would be in the end,

14. Na render said to Reshma, “I am fine and fit.”
Narendra told Reshma that he was fine and fit.

15. Rohan said to Kathir, “I went to my maternal uncle’s home.”
Rohan told Kathir that he had gone to his maternal uncle’s home.

We hope the data given here will benefit you to the fullest extent at the time of preparation. For better understanding of English subject this Samacheer Kalvi 10th English Answers for Class 10th English Grammar Do As Directed Transformation and Synthesis PDF is the best resource. Download & ace up your preparation. Keep in touch with us and get the latest information on Tamilnadu State board Textbook Answers PDF.

Looking to improve English skills and gain more subject knowledge then the best resources that you can use here is Samacheer Kalvi 10th English Solutions for Picture Comprehension Questions and Answers.

In the Samacheer Kalvi 10th English Guide for textbook solutions, subject experts covered all types of questions and answers related to the topics, quick notes, summary, solved & unsolved exercises, etc. If you are planning to prepare Chapter via textbook, then you’re suggested to go with this Samacheer Kalvi 10th English Book Solutions Questions and Answers PDF for better understanding and preparation.

Tamilnadu Samacheer Kalvi 10th English Picture Comprehension

English Subject experts who are having max years of experience prepared this Tamilnadu State Board Solutions for 10th English Picture Comprehension Questions and Answers. They have explained all the topics covered in the board prescribed latest syllabus in a simple way to understand easily. So, students can prepare English from this Samacheer Kalvi 10th English Book Questions and Answers PDF. Download the Tamilnadu State Board 10th English Workbook Answers PDF by accessing the below links and learn properly for the final exams to score well.

Look at the picture given below and answer the following question in one or two sentences of your own:
1.

(a) What is funny about this picture?
A donkey carrying a car in its cart.

(b) Can you guess why the car rides over a cart?
Perhaps the car cannot be repaired.
So, It is taken to a scrap dealer.

(c) Why does the driver sit on the car?
Perhaps the driver wants to stay safe. So, he is seated on the car.

(d) Will PETA approve of this practice? Why?
No, PETA will object as the poor animal is over burdened.

(e) Is there a hidden message pertaining to environment? What is it?
Yes, if we deplete the fossil fuels in such a rapid pace, cars will be there but we would need donkeys to pull them or carry them.

2.

(a) What is the man doing?
The man is taking a photo.

(b) What is he?
He is a wild life photographer.

(c) Do leopards always behave like the one in the picture?
No, leopards stay away from humans

(d) Why does the leopard cub trust the photographer?
The young cub knows intuitively that the photographer loves wild animals. It just reciprocates his love and trust.

(e) Why do we have very few wild life photographers?
To shoot animals with a camera when they roam freely in the woods is very risky. So, we have very few wild life photographers.

3.

(a) What are these athletes involved in?
These athletes are involved in a Marathon race.

(b) Do the athletes belong to the same nation? How?
No, the athletes are from different nations.

(c) Why does this picture appeal to you?
One of the athlete regards her peer as a fellow human and not as a competitor and she gives him water. It is more appealing to me because they are physically challenged

(d) Why is the Marathon race challenge?
One has to ran a very long distance. This requires high energy levels and pacing of the running cleverly. Clever ones run a steady pace for a long time. They accelerate speed in the last lap when most others are exhausted.

(e) What do you learn from this picture?
If a differently-abled person with no hands could take part in a Marathon race with confidence, we could also face challenges in life with confidence.

4.

(a) How is education important to boys and girls from low-income groups?
Education is a tune-tested weapon against poverty. So, it is important for boys and girls from low-income groups.

(b) How is this classroom different’?
In this classroom, students are seated very close to the teacher in a semi-circle. The teacher-student ratio is extremely good.

(c) What is the advantage of this strategic seating arrangement?
The teacher can look at everyone’s face and even the meekest voices of children can he heard. A good rapport is possible. .

(d) Arc the children misusing freedom? How?
No, the children observe classroom mies. A boy raises his hand to express his views on a particular topic.

5.

(a) What picture is this?
The picture is a Boarding pass.

(b) Name the mode of transportation.
The mode of transportation is Arop1ane.

(e) Which gate should the passenger enter through?
The passenger should enter through Gate B42.

(d) When is the flight expected to take off?
The flight is expected to take off at 11:40

(e) Is the flight journey by economical class?
No, the flight journey is by First class and not economical class.

We hope the data given here will benefit you to the fullest extent at the time of preparation. For better understanding of English subject this Samacheer Kalvi 10th English Answers for Class 10th English Picture Comprehension PDF is the best resource. Download & ace up your preparation. Keep in touch with us and get the latest information on Tamilnadu State board Textbook Answers PDF.

Looking to improve English skills and gain more subject knowledge then the best resources that you can use here is Samacheer Kalvi 10th English Solutions for Slogan Writing Questions and Answers.

In the Samacheer Kalvi 10th English Guide for textbook solutions, subject experts covered all types of questions and answers related to the topics, quick notes, summary, solved & unsolved exercises, etc. If you are planning to prepare Chapter via textbook, then you’re suggested to go with this Samacheer Kalvi 10th English Book Solutions Questions and Answers PDF for better understanding and preparation.

Tamilnadu Samacheer Kalvi 10th English Slogan Writing

English Subject experts who are having max years of experience prepared this Tamilnadu State Board Solutions for 10th English Slogan Writing Questions and Answers. They have explained all the topics covered in the board prescribed latest syllabus in a simple way to understand easily. So, students can prepare English from this Samacheer Kalvi 10th English Book Questions and Answers PDF. Download the Tamilnadu State Board 10th English Workbook Answers PDF by accessing the below links and learn properly for the final exams to score well.

Match the products with their slogans
1.

(i)	Glass	(a)	A comfortable sole in a cosy hole
(ii)	Shoes	(b)	Bring Switzerland into your room
(iii)	Tooth Paste	(c)	Handle with care
(iv)	Air-conditioner	(d)	Use for a while and get a sparkling smile

Answer:
(i) – (c)
(ii) – (a)
(iii) – (d)
(iv) – (b)

2.

(i)	Detergent	(a)	Doorstep to knowledge and information
(ii)	Shampoo	(b)	Rubs away everything but the past
(iii)	Eraser	(c)	Less foam easy to clean
(iv)	Computer	(d)	Leaves your hair smooth and silky

Answer:
(i) – (c)
(ii) – (d)
(iii) – (b)
(iv) – (a)

3

(i)	Camera	(a)	Have a vision – Make a decision
(ii)	Motorbike	(b)	No more summer; chillers is here
(iii)	Vote	(c)	Say cheese and freeze
(iv)	Ice-cream	(d)	For extra mile and smile

Answer:
(i) – (c)
(ii) – (d)
(iii) – (a)
(iv) – (b)

4.

(i)	Tea	(a)	Increase your word power
(d)	Watch	(b)	The world is in your room
(iii)	Newspaper	(c)	Sharp time for sharp people
(iv)	Dictionary	(d)	The cup that cheers you

Answer:
(i) – (d)
(ii) – (c)
(iii) – (b)
(iv) – (a)

5.

(i)	Mixer grinder	(a)	Enjoy the news and songs
(ii)	Credit Card	(b)	Your kitchen-mate
(iii)	Radio	(c)	Point out the passing of days
(iv)	Calendar	(d)	Buy now, pay later

Answer:
(i) – (b)
(ii) – (d)
(iii) – (a)
(iv) – (c)

6.

(i)	Five Star Hotel	(a)	Let there be fragrance around you
(ii)	Perfume	(b)	Eye it, buy it
(iii)	Basmati Rice	(c)	Live on the lap of luxury
(iv)	Maruti Baleno	(d)	Proven to ensure your health

Answer:
(i) (c)
(ii) (a)
(iii) (d) (iv) (b)

7.

(i)	Kodak	(a)	Show your care about the air
(ii)	Inverter	(b)	Share moments Share Life
(iii)	Pollution	(c)	Don’t destroy the greenery and spoil the scenery
(iv)	Save Trees	(d)	Let not frequent power cut worry you

Answer:
(i) – (b)
(ii) – (d)
(iii) – (a)
(iv) – (c)

8.

(i)	Wi-fi-Net connection	(a)	The less you bum, the more you earn
(ii)	Save Environment	(b)	Superfast wireless broadband
(iii)	Road Safety	(c)	Give a hoot, don’t pollute.
(iv)	Save Fuel	(d)	Normal Speed is all we need

Answer:
(i) – (b)
(ii) – (c)
(iii) – (d)
(iv) – (a)

Write a slogan for the given pictures
1.

Let’s grow green and make globe clean!

2.

Don’t drink and drive and you’ll stay alive

3.

It guarantees safety

4.

Lock and travel in peace

5.

Forget yourself with its milky taste

6.

Head gear, no fear

We hope the data given here will benefit you to the fullest extent at the time of preparation. For better understanding of English subject this Samacheer Kalvi 10th English Answers for Class 10th English Slogan Writing PDF is the best resource. Download & ace up your preparation. Keep in touch with us and get the latest information on Tamilnadu State board Textbook Answers PDF.

Looking to improve English skills and gain more subject knowledge then the best resources that you can use here is Samacheer Kalvi 10th English Solutions for Grammar Modals Questions and Answers.

In the Samacheer Kalvi 10th English Guide for textbook solutions, subject experts covered all types of questions and answers related to the topics, quick notes, summary, solved & unsolved exercises, etc. If you are planning to prepare Chapter via textbook, then you’re suggested to go with this Samacheer Kalvi 10th English Book Solutions Questions and Answers PDF for better understanding and preparation.

Tamilnadu Samacheer Kalvi 10th English Grammar Modals

English Subject experts who are having max years of experience prepared this Tamilnadu State Board Solutions for 10th English Grammar Modals Questions and Answers. They have explained all the topics covered in the board prescribed latest syllabus in a simple way to understand easily. So, students can prepare English from this Samacheer Kalvi 10th English Book Questions and Answers PDF. Download the Tamilnadu State Board 10th English Workbook Answers PDF by accessing the below links and learn properly for the final exams to score well.

General Characteristics Of Modals
1. Modals are never used alone. A Principal verb is either present or implied;
as—
I can sing. He will help you.

2. Modals do not change according to the number or person of the subject;
as—
I can. We can. You can. He can. They can. etc.
I may. We may. You may. He may. They may. etc.

3. Modals have no Infinitive, Present Participle or Past Participle forms.
4. Modals cannot be used in all the tenses. When a modal does not fall in this pattern, it works as a Principal Verb;
as—
God willed so.
Heiny needs a pen.
Malathi dared to go into the dark forest.
(Here will, need and dare are used as main verbs)

Relationship of Modals with Tenses
(i) May, can, shall and will are in present forms while might, could, should and would are their past forms.
The two forms express different meanings, but usually no difference of time, e.g. the difference between may and might is often that of degree of probability,

as—
Sheela may come today. (possibility/likely to happen)
Sandra might come today. (remote possibility/less likely)

(ii) However, if the verb in the main clause is in the past tense, the forms might, could, should and would serve as regular past tenses;

as—

1. He said, “I can help you.”
   He said that he could help her.
2. You said, “She will come back soon.”
   You said that she would come back soon.
3. Sheetal said, “May I use this pen, madam?”
   Sheetal asked her teacher if she might use that pen.

(iii) When we want to express the past time in verb phrases involving modals, we use the Present Perfect Tense of the Principal Verb;
as-
Senthil must have reached home by now.
You ought to have told me all the facts.

Quasi / Semi Modals
Quasi modals are also called semi-modals. There are four quasi modals: ‘used to’, ‘need to’, ‘dare to’ and ‘ought to’.

Fill in the blanks choosing the correct modal given within the brackets to suit the sentence.
1. They ……………………….. (can/might) be away for the weekend but I’m not sure.
2. You ……………………….. (may/might) leave now if you want to.
3. ……………………….. (Could/Might) you open the door a bit, please?
4. He ……………………….. (can/could) be a Bengali, judging by his accent.
5 ……………………….. (May/Can) you play the violin?
6. Listen, carefully, you (may not/might not) ……………………….. speak during this exam.
7. They ……………………….. (can’t/may not) still be out!
8. You ……………………….. (mustn’t/might not) smoke on the bus.
9. With luck, tomorrow ……………………….. (can/could) be a rainy day.
10. You (can/might) ……………………….. be right but I’m going back to check anyway.
11. I don’t know Hindi and so I ……………………….. (must/should) learn before I go to Delhi.
12. ……………………….. you stand upside down for a minute? No, I (can’t/could)
13. You ……………………….. leave small objects lying around. Children swallow it by mistake, (shouldn’t /may)
14. This is a public place. You ……………………….. (must/should) not smoke.
15. ……………………….. (May/Can) I ask a question?
16. He had been toiling for the past fifteen hours. He ……………………….. (must/should) be exhausted.
17. Drivers ……………………….. (must/should) stop the vehicle when they see the red signal.
18. According to the weather forecast, it ……………………….. (will/may) rain tomorrow.
19. Please try to reach the venue before me. I ……………………….. (will/may) be late.
20 ……………………….. (Could/Would) you mind lifting this box for me?
21. Anyone ……………………….. (can/could) come for a trial but it was up to Sir to decide who to accept.
22. Ajit was called aside and suggested that he ……………………….. (must/should) bring me back when I was a little older.
23. My induction into the Mumbai cricket circuit ……………………….. (could/may) have ended in failure.
24. I was delighted and I ……………………….. (must/should) say it was an opportunity that transformed my life.
25. The schedule was rigorous and Sachin ……………………….. (must/would) be exhausted by the end of the day.
26. I am sure that Zigzag ……………………….. (must/should) be Uncle Somu’s pet snake.
27. Some ……………………….. (might/can) be your best friend, but most of them were absolute nuisances!
28. You ……………………….. (may/can’t) deny that it was a great hit with everyone.
29. ……………………….. (Can/May) I take Zigzag to school, Papa?
30. He ……………………….. (can/could) even recite French Poetry!
Answer:
1. might 2. may 3. Could 4. could 5. Can 6. may not 7. can’t 8. mustn’t 9. could 10. might
11. must 12. Could/can’t 13. shouldn’t/may 14. must 15. May 16. must 17. should 18. will 19. may 20. Would
21. could 22. should 23. could 24. must 25. would 26. must 27. might 28. can’t 29. May. 30. can

We hope the data given here will benefit you to the fullest extent at the time of preparation. For better understanding of English subject this Samacheer Kalvi 10th English Answers for Class 10th English Grammar Modals PDF is the best resource. Download & ace up your preparation. Keep in touch with us and get the latest information on Tamilnadu State board Textbook Answers PDF.

Students who are preparing for the Science exam can download this Tamilnadu State Board Solutions for Class 10th Science Chapter 23 from here for free of cost. These Tamilnadu State Board Textbook Solutions PDF cover all 10th Science Visual Communication Book Back Questions and Answers.

All these concepts of Chapter 23 Visual Communication are explained very conceptually by the subject teachers in Tamilnadu State Board Solutions PDF as per the prescribed Syllabus & guidelines. You can download Samacheer Kalvi 10th Science Book Solutions Chapter 23 Visual Communication State Board Pdf for free from the available links. Go ahead and get Tamilnadu State Board Class 10th Science Solutions of Chapter 23 Visual Communication.

Tamilnadu Samacheer Kalvi 10th Science Solutions Chapter 23 Visual Communication

Kickstart your preparation by using this Tamilnadu State Board Solutions for Class 23th Science Chapter 23 Visual Communication Questions and Answers and get the max score in the exams. You can cover all the topics of Chapter 23 easily after studying the Tamilnadu State Board Class 23th Science Textbook solutions pdf. Download the Tamilnadu State Board Science Chapter 23 Visual Communication solutions of Class 23th by accessing the links provided here and ace up your preparation.

Samacheer Kalvi 10th Science Visual Communication Textual Evaluation Solved

I. Choose the correct answer:

Question 1.
Which software is used to create animation?
(a) Paint
(b) PDF
(c) MS Word
(d) Scratch.
Answer:
(d) Scratch.

Question 2.
All files are stored in the:
(a) Folder
(b) box
(c) Pai
(d) Scanner
Answer:
(a) Folder

Question 3.
Which is used to build scripts?
(a) Script area
(b) Block palette
(c) Stage
(d) Sprite.
Answer:
(a) Script area

Question 4.
Which is used to edit programs?
(a) Inkscape
(b) Script editor
(c) Stage
(d) Sprite
Answer:
(b) Script editor

Question 5.
Where you will create the category of blocks?
(a) Block palette
(b) Block menu
(c) Script area
(d) Sprite.
Answer:
(b) Block menu

II. Match the following:

Question 1.

1. Script Area	(a) Type notes
2. Folder	(b) Animation software
3. Scratch	(c) Edit programs
4. Costume editor	(d) Store files
5. Notepad	(e) Build Scripts

Answer:

1. (e) Build Scripts
2. (d) Store files
3. (b) Animation software
4. (c) Edit programs
5. (a) Type notes.

III. Answer the following:

Question 1.
What is Scratch?
Answer:
‘Scratch’ is a software used to create animations, cartoons and games easily. Scratch, on the other hand, is a visual programming language. It was developed in the Massachusetts Institute of Technology (MIT) Media Lab to make programming easier and more fun to learn.

Question 2.
Write a short note on editor and its type?
Answer:
There are two types of editors. They are (i) Script editor (ii) Costume editor.
Editors are used to edit your programs or your sprite’s pictures. The script editor has three main parts: Script area, Block menu and Block palette. When costume editor tab is chosen, Click → File / New to create new project.

Question 3.
What is Stage?
Answer:
The stage is the background appearing when we open the scratch window. The background will most often be white. You can change the background colour as you like.
Question 4.
What is Sprite?
Answer:
The characters on the background of a scratch window are known as sprite. Usually a cat appears as a sprite when the scratch window is opened. The software provides facilities to make alternations in sprite.

Samacheer Kalvi 10th Science Visual Communication Additional Questions Solved

I. Choose the correct answer.

Question 1.
The characters on the background of a scratch window are known as _______.
(a) stage
(b) screen
(c) sprite
(d) script.
Answer:
(c) sprite

Question 2.
Which button is click, it shows the list of all programs in the computer?
(a) My computer
(b) START
(c) Recycle Bin
(d) Explorer
Answer:
(b) START

Question 3.
Choose the correct pair for the following _______.
(a) Stage – bottom left
(b) Sprite list – top left
(c) Script tab – right
(d) None of these.
Answer:
(c) Script tab – right

Question 4.
The device which helps in explaining the concepts easily through pictures is known as:
(a) Visual communication device
(b) Paint
(c) Notepad
(d) Scratch
Answer:
(a) Visual communication device

Question 5.
Choose the correct statement from the following _______.
(a) The output we get from any application is called folder.
(b) Cinema is a good example of VCD.
(c) The characters on the background of a scratch window are known as a stage.
(d) The scratch editor has four main parts.
Answer:
(b) Cinema is a good example of VCD.

Question 6.
Which company was developed by Scratch software?
(a) Massachusetts Institute of Technology (MIT)
(b) Microsoft corporation
(c) Sun micro system
(d) Oracle corporation
Answer:
(a) Massachusetts Institute of Technology (MIT)

Question 7.
The output we get from any application is commonly referred to as _______.
(a) file
(b) folder
(c) hardware
(d) software.
Answer:
(a) file

Question 8.
Choose the correct pair:
(a) Script – Event
(b) Mouse – Output
(c) Visual – blackboard
(d) NEW – Start
Answer:
(a) Script – Event

Question 9.
When we _____ on the mouse, the popup menu appears.
(a) right – click
(b) left click
(c) click
(d) right.
Answer:
(a) right-click

Question 10.
Choose the correct statement:
(a) The scratch editor has two main parts.
(b) The stage background will most often be black.
(c) Block menu, where you build scripts
(d) The script editor right pane also contains two additional tabs, costumes and sounds.
Answer:
(d) The script editor right pane also contains two additional tabs, costumes and sounds.

Question 11.
The list of all programs loaded in the computer is shown when you click _______ button.
(a) Home
(b) list
(c) All programs
(d) start.
Answer:
(d) start.

Question 12.
Which device helps in explaining the concepts easily through pictures?
(a) Audiometer
(b) Video meter
(c) Visual audio device
(d) Visual communication device.
Answer:
(d) Visual communication device.

Question 13.
Which one of the following is a good example of a visual communication device?
(a) Theatre
(b) Cinema
(c) Exhibitions
(d) poster making.
Answer:
(b) Cinema

Question 14.
VCD means _______.
(a) Virtual compact disk
(b) Video compact disc
(c) Visual contract device
(d) Visual communication device.
Answer:
(d) Visual communication device.

Question 15.
Which one of the following is a visual programming language?
(a) Visual Basic
(b) Scratch
(c) Visual C++
(d) paint.
Answer:
(b) Scratch

Question 16.
Expand MIT _______.
(a) Maritime Institute of Technology
(b) Madras Institute of Technology
(c) Massachusetts Institute of Technology
(d) Maldives Institute of Technology.
Answer:
(c) Massachusetts Institute of Technology

Question 17.
The Scratch editors consists of ______ main parts.
(a) 2
(b) 3
(c) 4
(d) 5.
Answer:
(b) 3

Question 18.
Pick the odd one out _______.
(a) Stage
(b) Screen
(c) Sprite
(d) Script editor.
Answer:
(b) Screen

Question 19.
_______ is the background appearing when we open the scratch Window.
(a) Stage
(b) Screen
(c) Sprite
(d) Script.
Answer:
(a) Stage

Question 20.
What is the default colour of the stage?
(a) red
(b) yellow
(c) white
(d) black.
Answer:
(c) white

Question 21.
Find the correct statement from the following?
(a) The background colour of the stage can be changed.
(b) The background colour of the stage cannot be changed.
Answer:
(a) The background colour of the stage can be changed.

Question 23.
The _____ pane also contains two additional tabs like costumes and sounds.
(a) left
(b) right
(c) centre
(d) bottom.
Answer:
(b) right

Question 24.
Find the false statement from the following.
(a) When the costume tab is chosen, the costume editor appears in red colour.
(b) When the costume tab is chosen, the costume editor appears in blue colour.
Answer:
(b) When the costume tab is chosen, the costume editor appears in blue colour.

Question 25.
What is the command used to create a new project?
(a) File →New
(b) File → project New
(c) File → New project
(d) File → project.
Answer:
(a) File → New

Question 26.
Click the _____ flag at the top right comer of the stage to run your program.
(a) red
(b) blue
(c) green
(d) yellow.
Answer:
(c) green

Question 27.
Which is not a part of script editor?
(a) sprite
(b) script area
(c) Block menu
(d) Block palette.
Answer:
(a) sprite

Question 28.
Click the scripts tab and find the play sound block from the ________ menu.
(a) scripts
(b) events
(c) sound
(d) audio.
Answer:
(c) sound

II. Match the following:

Question 1.

1. VCD	(a) Storage space
2. File	(b) Cinema
3. Folder	(c) Software
4. Scratch	(d) Specific purpose

Answer:

1. (b) Cinema
2. (d) Specific purpose
3. (a) Storage space
4. (c) Software.

Question 2.

1. Script tabs	(a) Unknown place
2. Build scripts	(b) Blocks tab
3. Right pane	(c) Script area
4. Guide board	(d) Costumes and sounds

Answer:

1. (b) Blocks tab
2. (c) Script area
3. (d) Costumes and sounds
4. (a) Unknown place.

III. Fill in the blanks:

Question 1.
______ and ____ plays a vital role in the working of the computer.
Answer:
Software, hardware.

Question 2.
In Windows OS, ______ application is used to draw pictures.
Answer:
paint.

Question 3.
In Windows OS, we can collect our notes in ______ application.
Answer:
Notepad.

Question 4.
The ______ tab on the right contains the blocks tabs and scripts area.
Answer:
Scripts.

Question 5.
Click the menu _____ drag a when green flag clicked the block to the scripts area.
Answer:
Script → Event.

Question 6.
Sound is present in _____ option.
Answer:
Script.

Question 7.
Visual programming was developed in the _______.
Answer:
Massachusetts Institute of Technology (MIT).

IV. Short Answer Questions

Question 1.
Define file.
Answer:
The output we get from any application is commonly referred to as ‘file’. Therefore the application for the specific purposes determines the nature of the file.

Question 2.
How can we save data and information in computer?
Answer:
We can save data and information in folders which accommodate a single file or multiple files. So all files are stored in the folder.

Question 3.
Define VCD. (Visual Communication Device)?
Answer:
The device which helps in explaining the concepts easily through pictures is known as ‘Visual Communication Device’. For example photos, audiovisuals, drawings, animations all these can be created easily with the help of the computer. Cinema is a good example of ‘Visual Communication Device’.

Question 4.
Write any four operating systems?
Answer:

1. Windows
2. UNIX
3. LINUX
4. iOS.

Question 5.
What are the three main parts of the script editor?
Answer:
The script editor has three main parts:

• Script area: Where you build scripts.
• Block menu: Where you choose the category of blocks (programming statements) to use.
• Block palette: Where you choose the block to use.

Question 6.
How will you add sound using the costume tab?
Answer:
When the Costumes tab is chosen, the costume editor, Click File/New to create a new project and enter a project name.
Click File / New to create a new project and enter a project name.

Adding Sound:

1. Click Spritel in the sprite list and click the Sounds tab.
2. Try the meow sound already there. If you don’t like it, click the speaker icon to choose a different sound from the sound library.
3. Click the Scripts tab and find the play sound block from the Sound menu. Add this block to the when space key pressed script. (Select the sound you want from the drop-down list.)
4. Run your program.

Question 7.
Explain how will you create a new project?
Answer:
Click File / New to create a new project and enter a project name.

V. Long Answer Questions

Question 1.
Explain adding sound with an example.
Answer:
Adding Sound:

1. Click Spritel in the sprite list and click the Sounds tab.
2. Try the meow sound already there. If you don’t like it, click the speaker icon to choose a different sound from the sound library.
3. Click the Scripts tab and find the play sound block from the Sound menu. Add this block when space key pressed script. (Select the sound you want from the drop-down list.)
4. Run your program.

Example:
Program for print the word “Hello” with sound:

1. Click events in script option.

2. Drag “When Clicked” tab to script area.

3. Click Looks in script option. Drag “say” to script area.

4. Type “Hello “ word in say tab.

5. Click sounds in script option. Drag play sound to script area. Choose the hello sound from the audio file.

6. From File menu choose the Save option.

7. Click the green flag at the top right comer of the stage window to run the program.

Question 2.
Explain how will you give movements and loops. Give an example.
Answer:
Click the menu Script → Event, drag a when green flag clicked a block to the scripts area. Your scripts area should look like this:

Click the menu Script → Motion menu, drag a goto x : 0, y : 0 blocks to the scripts area and snap it to the bottom of the when green flag clicked the block.
Your script should look like this:

Add a move 10 steps block to the bottom of your script and change the 10 into 100.

Click the green flag at the top right comer of the stage to run your program.

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Tamilnadu Samacheer Kalvi 10th Science Solutions Chapter 4 Electricity

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Samacheer Kalvi 10th Science Electricity Textual Solved Problems

10th Science Electricity Lesson Book Back Answers Question 1.
A charge of 12 coulomb flows through a bulb in 5 seconds. What is the current through the bulb?
Solution:
Charge Q = 12 C, Time t = 5s. Therefore,
Current \(\mathrm{I}=\frac{\mathrm{Q}}{\mathrm{t}}=\frac{12}{5}=2.4 \mathrm{A}\).

Electricity Class 10 Book Back Answers Question 2.
The work done in moving a charge of 10 C across two points in a circuit is 100 J. What is the potential difference between the points?
Solution:
Charge Q = 10 C, Work Done W = 100 J
Potential Difference \(\mathrm{V}=\frac{\mathrm{W}}{\mathrm{Q}}=\frac{100}{10}\)
Therefore, V = 10 volt.

Electricity Book Back Answers Question 3.
Calculate the resistance of a conductor through which a current of 2 A passes, when the potential difference between its ends is 30 V.
Solution:
Current through the conductor I = 2 A,
Potential Difference V = 30 V
From Ohm’s Law: R = \(\frac{\mathrm{V}}{\mathrm{I}}\)
Therefore, R = \(\frac{30}{2}\) = 15 Ω.

10th Science 1 Chapter 4 Question 4.
The resistance of a wire of length 10 m is 2 ohm. If the area of cross-section of the wire is 2 × 10^-7 m², determine its

1. Resistivity
2. Conductance
3. Conductivity

Solution:
Given: Length, L = 10 m, Resistance, R = 2 ohm
and Area, A = 2 × 10^-7 m²

10th Science Electricity Lesson Question 5.
Three resistors of resistances 5 ohms, 3 ohms and 2 ohms are connected in series with 10 V battery. Calculate their effective resistance and the current flowing through the circuit.
Solution:
R₁ = 5 Ω, R₂ = 3 Ω, R₃ = 2 Ω, V = 10 V
R_S = R₁ + R₂ + R₃ = 5 + 3 + 2 = 10 Ω
The current, \(\mathrm{I}=\frac{\mathrm{V}}{\mathrm{R}_{\mathrm{s}}}=\frac{10}{10}=1 \mathrm{A}\).

Numericals On Joule’s Law Of Heating Class 10 Question 6.
An electric heater of resistance 5 Ω is connected to an electric source. If a current of 6 A flows through the heater, then find the amount of heat produced in 5 minutes.
Solution:
Given resistance R = 5 Ω, Current I = 6 A,
Time t = 5 minutes = 5 × 60 s = 300 s
Amount of heat produced, H = I²Rt = 6² × 5 × 300 = 54000 J
Hence, H = 54000 J.

Numericals On Ohm’s Law Class 10 Question 7.
Two bulbs are having the ratings as 60 W, 220 V and 40 W, 220 V respectively. Which one has a greater resistance?
Solution:
Electric power \(\mathrm{P}=\frac{\mathrm{V}^{2}}{\mathrm{R}}\)
For the same value of V, R is inversely proportional to P.
Therefore, the lesser the power, the greater the resistance
Hence, the bulb with 40 W, 220 V rating has greater resistance.

Class 10 Electricity Book Back Answers Question 8.
Calculate the current and the resistance of a 100 W, 200 V electric bulb in an electric circuit.
Solution:
Power P = 100 W and Voltage V = 200 V
Power P = VI
So, Current, I = \(\frac{P}{V}\) = \(\frac{100}{200}\) = 0.5 A
Resistance, R = \(\frac{\mathrm{V}}{\mathrm{I}}\) = \(\frac{200}{0.5}\) = 400 Ω.

Samacheer Kalvi Guru 10th Science Question 9.
In the circuit diagram is given below resistors R₁, R₂ and R₃ of 5 Ω, 10 Ω and 20 Ω respectively are connected as shown in fig.
Calculate:
(A) Current through each resistor
(B) The total current in the circuit
(C) The total resistance in the circuit

Solution:
(A) Since the resistors are connected in parallel, the potential difference across each resistor is same (i.e. V = 10 V)
Therefore, the current through R₁ is, \(\mathrm{I}_{1}=\frac{\mathrm{V}}{\mathrm{R}_{1}}=\frac{10}{5}=2 \mathrm{A}\)
Current through R₂, \(\mathrm{I}_{2}=\frac{\mathrm{V}}{\mathrm{R}_{2}}=\frac{10}{10}=1 \mathrm{A}\)
Current through R₃, \(I_{3}=\frac{V}{R} \quad \frac{10}{20}=0.5 A\)

(B) Total current in the circuit, I = I₁ + I₂ + I₃ = 2 + 1 + 0.5 = 3.5 A

(C) Total resistance in the circuit

Hence, \(\mathrm{R}_{\mathrm{p}}=\frac{20}{7}=2.857 \Omega\).

Question 10.
Three resistors of 1 Ω, 2 Ω and 4 Ω are connected in parallel in a circuit. If a 1 Ω resistor draws a current of 1 A, find the current through the other two resistors.
Solution:
R₁ = 1 Ω, R₂ = 2 Ω, R₃ = 4 Ω, Current I₁ = 1 A
The potential difference across the 1 Ω resistor = I₁R₁ = 1 × 1 = 1 V
Since, the resistors are connected in parallel in the circuit, the same potential difference will exist across the other resistors also.
So, the current in the 2 Ω resistor, \(\frac{\mathrm{V}}{\mathrm{R}_{2}}=\frac{1}{2}=0.5 \mathrm{A}\)
Similarly, the current in the 4 Ω resistor, \(\frac{\mathrm{V}}{\mathrm{R}_{3}}=\frac{1}{4}=0.25 \mathrm{A}\).

Samacheer Kalvi 10th Science Electricity Textual Evaluation

I. Choose the best answer

Question 1.
Which of the following is correct?
(a) Rate of change of charge is electrical power.
(b) Rate of change of charge is current.
(c) Rate of change in energy is current.
(d) Rate of change of current is a charge.
Answer:
(b) Rate of change of charge is current

Question 2.
SI unit of resistance is ______.
(a) mho
(b) joule
(c) ohm
(d) ohmmeter.
Answer:
(c) ohm

Question 3.
In a simple circuit, why does the bulb glow when you close the switch?
(a) The switch produces electricity.
(b) Closing the switch completes the circuit.
(c) Closing the switch breaks the circuit.
(d) The bulb is getting charged.
Answer:
(d) The bulb is getting charged.

Question 4.
Kilowatt-hour is the unit of _______.
(a) resistivity
(b) conductivity
(c) electrical energy
(d) electrical power.
Answer:
(c) electrical energy

II. Fill in the blanks

Question 1.
When a circuit is open, ______ cannot pass through it.
Answer:
Current.

Question 2.
The ratio of the potential difference to the current is known as ______.
Answer:
Ohm’s law.

Question 3.
The wiring in a house consists of ______ circuits.
Answer:
domestic electric

Question 4.
The power of an electric device is a product of _____ and ______.
Answer:
electric current, the potential difference.

Question 5.
LED stands for ______.
Answer:
Light Emitting Diode.

III. State whether the following statements are true or false: If false correct the statement.

Question 1.
Ohm’s law states the relationship between power and voltage.
Answer:
False.
Correct Statement: Ohm’s law states the relationship between potential difference and current.

Question 2.
MCB is used to protect household electrical appliances.
Answer:
True.

Question 3.
The SI unit for electric current is the coulomb.
Answer:
False.
Correct Statement: The SI unit of electric current is Ampere.

Question 4.
One unit of electrical energy consumed is equal to 1000 kilowatt-hour.
Answer:
True.

Question 5.
The effective resistance of three resistors connected in series is lesser than the lowest of the individual resistances.
Answer:
False.
Correct Statement: The effective resistance of three resistors connected in series is greater than the highest of the individual resistance.

IV. Match the items in column-I to the items in column-II:

Question 1.

1. Electric current	(a) Volt
2. Potential difference	(b) Ohmmeter
3. Specific resistance	(c) Watt
4. Electrical power	(d) Joule
5. Electrical energy	(e) Ampere

Answer:
1. (e) Ampere
2. (a) Volt
3. (b) Ohmmeter
4. (c)Watt
5. (d) Joule

V. Assertion and Reason Type Questions

Mark the correct choice as
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
(b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
(c) If the assertion is true, but the reason is false.
(d) If the assertion is false, but the reason is true.

Question 1.
Assertion: Electric appliances with a metallic body have three wire connections.
Reason: Three – pin connections reduce heating of the connecting wires
Answer:
(c) If the assertion is true, but the reason is false.
Correct Reason: Three – pin connections to protect the electrical shocking. Because appliances carry high electric current.

Question 2.
Assertion: In a simple battery circuit the point of highest potential is the positive terminal of the battery.
Reason: The current flows towards the point of the highest potential.
Answer:
(c) If the assertion is true, but the reason is false.
Correct Reason: The current flows towards the points of the lower potential.

Question 3.
Assertion: LED bulbs are far better than incandescent bulbs.
Reason: LED bulbs consume less power than incandescent bulbs.
Answer:
(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.

VI. Very Short Answer Questions.

Question 1.
Define the unit of current.
Answer:
The SI unit of electric current is ampere (A). The current flowing through a conductor is said to be one ampere when a charge of one coulomb flows across any cross-section of a conductor in one second. Hence,
1 ampere = \(\frac{1 \text { coulomb }}{1 \text { second }}\).

Question 2.
What happens to the resistance, when the conductor is made thicker?
Answer:
Resistance of a conductor is inversely proportional to the area of cross section of the conductors. Hence, resistance is inversely proportional to square of the radius of the conductor.
R ∝ \(\frac{1}{A}\)
R ∝ \(\frac{1}{r^2}\)
When a conductor is made thicker, radius will be increased and so its resistance will be decreased.

Question 3.
Why is tungsten metal used in bulbs, but not infuse wires?
Answer:
Because tungsten has a high melting point it is used in blubs. It cannot be used in fuse wires because in fuse wires the material must have a low melting point.

Question 4.
Name any two devices, which are working on the heating effect of the electric current.
Answer:
(i) Electric heater
(ii) Fuse wire

VII. Short Answer Questions.

Question 1.
Define electric potential and potential difference.
Answer:
Electric Potential: The electric potential at a point is defined as the amount of work done in moving a unit positive charge from infinity to that point against the electric force.

Electric Potential Difference: The electric potential difference between two points is defined as the amount of work done in moving a unit positive charge from one point to another point against the electric force.

Question 2.
What is the role of the earth wire in domestic circuits?
Answer:
This wire provides a low resistance path to the electric current. The earth wire sends the current from the body of the appliance to the Earth, whenever a live wire accidentally touches the body of the metallic electric appliance. Thus, the earth wire serves as a protective conductor, which saves us from electric shocks.

Question 3.
State Ohm’s law.
Answer:
According to Ohm’s law, at a constant temperature, the steady current ‘I’ flowing through a conductor is directly proportional to the potential difference ‘V’ between the two ends of the conductor.
I ∝ V
V = IR.

Question 4.
Distinguish between the resistivity and conductivity of a conductor.
Answer:

Resistivity	Conductivity
1. It is the resistance of a conductor of unit length and unit area of cross-section.	1. It is the reciprocal of electrical resistivity of a material.
2. Its unit is ohm metre	2. Its unit is ohm-1 metre-1 or mho metre-1
3. It is the measure of the resisting power of a specified material to the passage of an electric current.	3. It is the measure of its ability to pass the current through it.

Question 5.
What connection is used in domestic appliances and why?
Answer:
Parallel connection is used in domestic appliances. When any disconnection of one circuit in our home, does not affect the other circuit.

VIII. Long Answer Questions.

Question 1.
With the help of a circuit diagram derive the formula for the resultant resistance of three resistances connected:
(a) in series and
(b) in parallel
Answer:
(a) Resistors in Series:
A series circuit connects the components one after the other to form a ‘single-loop’. A series circuit has only one loop through which current can pass. If the circuit is interrupted at any point in the loop, no current can pass through the circuit and hence no electric appliances connected in the circuit will work. Series circuits are commonly used in devices such as flashlights. Thus, if

(i) Resistors are connected end to end so that the same current passes through each of them, then they are said to be connected in series.

(ii) Let, three resistances R₁, R₂ and R₃ be connected in series.

(iii) Let the current flowing through them be I.

(iv) According to Ohm’s Law, the potential differences V₁, V₂ and V₃ across R₁ , R2 and R₃ respectively, are given by:
V₁ = IR₁ …. (1)
V₂ = IR₂ …. (2)
V₃ = IR₃ …. (3)
The sum of the potential differences across the ends of each resistor is given by:
V = V₁ + V₂ + V₃
using equations (1), (2) and (3), we get
V = IR₁ + IR₂ + IR₃ …. (4)

(v) The effective resistor is a single resistor, which can replace the resistors effectively, so as to allow the same current through the electric circuit.

(vi) Let, the effective resistance of the series-combination of the resistors, be R_S. Then,
V = IR_S ….(5)
Combining equations (4) and (5)
IR_S = IR₁ + IR₂ + IR₃
R_S = R₁ + R₂ + R₃
Thus, we can understand that

(vii) When a number of resistors are connected in series, their equivalent resistance or effective resistance is equal to the sum of the individual resistances.

(viii) When V resistors of equal resistance R are connected in series, the equivalent resistance is ‘nR’. i.e., R_S = nR

(ix) The equivalent resistance in a series combination is greater than the highest of the individual resistances.

(b) Resistors in Parallel:
A parallel circuit has two or more loops through which current can pass. If the circuit is disconnected in one of the loops, the current can still pass through the other loop(s). The wiring in a house consists of parallel circuits.

(i) Consider that three resistors R₁, R₂ and R₃ are connected across two common points A and B.

(ii) The potential difference across each resistance is the same and equal to the potential difference between A and B. This is measured using the voltmeter.

(iii) The current I arriving at A divides into three branches I₁, I₂ and I₃ passing through R₁, R₂ and R₃ respectively.
According to the Ohm’s law, we have,
\(I_{1}=\frac{V}{R_{1}}\) …(1)
\(I_{2}=\frac{V}{R_{2}}\) ….(2)
\(I_{3}=\frac{V}{R_{3}}\) …. (3)
The total current through the circuit is given by
I = I₁ + I₂ + I₃
Using equations (1), (2) and (3), we get
\(\mathrm{I}=\frac{\mathrm{V}}{\mathrm{R}_{1}}+\frac{\mathrm{V}}{\mathrm{R}_{2}}+\frac{\mathrm{V}}{\mathrm{R}_{3}}\) …. (4)
Let the effective resistance of the parallel combination of resistors be R_P Then,
\(\mathrm{I}=\frac{\mathrm{V}}{\mathrm{R}_{\mathrm{P}}}\) …. (5)
Combining equations (4) and (5), we have
\(\frac{\mathrm{V}}{\mathrm{R}_{\mathrm{P}}}=\frac{\mathrm{V}}{\mathrm{R}_{1}}+\frac{\mathrm{V}}{\mathrm{R}_{2}}+\frac{\mathrm{V}}{\mathrm{R}_{3}}\)
\(\frac{1}{\mathrm{R}_{\mathrm{P}}}=\frac{1}{\mathrm{R}_{1}}+\frac{1}{\mathrm{R}_{2}}+\frac{1}{\mathrm{R}_{3}}\).

(iv) When a number of resistors are connected in parallel, the sum of the reciprocals of the individual resistances is equal to the reciprocal of the effective or equivalent resistance.

(v) When ‘n’ resistors of equal resistances R are connected in parallel, the equivalent resistance is \(\frac{\mathrm{R}}{n}\)
\(\frac{1}{\mathrm{R}_{\mathrm{P}}}=\frac{1}{\mathrm{R}}+\frac{1}{\mathrm{R}}+\frac{1}{\mathrm{R}} \ldots+\frac{1}{\mathrm{R}}=\frac{n}{\mathrm{R}}\)
Hence, \(\mathrm{R}_{\mathrm{P}}=\frac{\mathrm{R}}{n}\)

(vi) The equivalent resistance in a parallel combination is less than the lowest of the individual resistances.

Question 2.
(a) What is meant by electric current?
(b) Name and define its unit.
(c) Which instrument is used to measure the electric current? How should it be connected in a circuit?
Answer:
(a) Electric current is the rate of flow of charges in a conductor.
(b) The unit of current is ampere. The current flowing through a conductor is said to be one ampere, when a charge of one coulomb flows across any cross-section of a conductor, in one second. Hence,
1 ampere = \(\frac{1 coulomb}{1 second}\)
(c) Ammeter is used to measure electric current. Ammeter is always connected in series.

Question 3.
(a) State Joule’s law of heating.
(b) An alloy of nickel and chromium is used as the heating element. Why?
(c) How does a fuse wire protect electrical appliances?
Answer:
(a) The heat produced in the resistor is H = W = VQ
We know that the relation between the charge and current is Q = It.
Using this, we get H = VIt
From Ohm’s Law, V = IR. Hence, we have H = I²Rt
This is known as Joule’s law of heating.
Joule’s law of heating states that the heat produced in any resistor is:

• Directly proportional to the square of the current passing through the resistor. H = VIt
• Directly proportional to the resistance of the resistor. V = IR
• Directly proportional to the time for which the current is passing through the resistor. H = I²Rt

(b) An alloy of nickel and chromium is used as the heating element. Because:

• it has high resistivity
• it has a high melting point
• it is not easily oxidized.

(c) (i) The fuse wire is connected in series, in an electric circuit.
(ii) When a large current passes through the circuit, the fuse wire melts due to Joule’s heating effect and hence the circuit gets disconnected.
(iii) Therefore, the circuit and the electric appliances are saved from any damage.
(iv) The fuse wire is made up of a material whose melting point is relatively low.

Question 4.
Explain about domestic electric circuits, (circuit diagram not required)
Answer:
In our homes, electricity is distributed through the domestic electric circuits wired by the electricians. The first stage of the domestic circuit is to bring the power supply to the main-box from a distribution panel, such as a transformer. The important components of the main-box are: (i) a fuse box and (ii) a meter. The meter is used to record the consumption of electrical energy. The fuse box contains either a fuse wire or a Miniature Circuit Breaker (MCB). The function of the fuse wire or an MCB is to protect the household electrical appliances from overloading due to excess current.

An MCB is a switching device, which can be activated automatically as well as manually. It has a spring attached to the switch, which is attracted by an electromagnet when an excess current passes through the circuit. Hence, the circuit is broken and the protection of the appliance is ensured.

The electricity is brought to houses by one wire has a red insulation and is called the ‘live wire’. The other wire has a black insulation and is called the ‘neutral wire’. The electricity supplied to your house is actually an alternating current having an electric potential of 220 V. Both, the live wire and the neutral wire enter into a box where the main fuse is connected with the live wire. After the electricity meter, these wires enter into the main switch, which is used to discontinue the electricity supply whenever required. After the main switch, these wires are connected to live wires of two separate circuits.

Out of these two circuits, one circuit is of a 5 A rating, which is used to run the electric appliances with a lower power rating, such as tube lights, bulbs and fans. The other circuit is of a 15 A rating, which is used to two insulated wires. Out of these two wires, run electric appliances with a high power rating, such as air-conditioners, refrigerators, electric iron and heaters. It should be noted that all the circuits in a house are connected in parallel, so that the disconnection of one circuit does not affect the other circuit. One more advantage of the parallel connection of circuits is that each electric appliance gets an equal voltage.

Question 5.
(a) What are the advantages of LED TV on normal TV?
(b) List the merits of the LED bulb.
Answer:
(a) (i) It has a brighter picture quality.
(ii) It is thinner in size.
(iii) It uses less power and consumes very less energy.
(iv) Its life span is more
(v) It is more reliable

(b) (i) As there is no filament, there is no loss of energy in the form of heat. It is cooler than the incandescent bulb.
(ii) In comparison with the fluorescent light, the LED bulbs have a significantly low power requirement.
(iii) It is not harmful to the environment.
(iv) A wide range of colours is possible here.
(v) It is cost-efficient and energy-efficient.
(vi) Mercury and other toxic materials are not required.

IX. Numerical Problems:

Question 1.
An electric iron consumes energy at the rate of 420 W when heating is at the maximum rate and 180 W when heating is at the minimum rate. The applied voltage is 220 V. What is the current in each case?
Solution:
Case: 1
Power (P) = 420W
Applied Voltage (V) = 220V
Current \(\mathrm{I}=\frac{\mathrm{P}}{\mathrm{V}}=\frac{420}{220}=1.9 \mathrm{A}\)

Case: 2
Power (P) = 180 W
Applied Voltage (V) = 2.20 V
Current \(\mathrm{I}=\frac{\mathrm{P}}{\mathrm{V}}=\frac{180}{220}=0.8 \mathrm{A}\)

Question 2.
A 100-watt electric bulb is used for 5 hours daily and four 60 watt bulbs are used for 5 hours daily. Calculate the energy consumed (in kWh) in the month of January.
Answer:
Energy used by 100 W bulb is E = P × t
= 100 × 5 = 500 Wh
Energy used by four 60 W bulbs E = 4 × 60 × 5 = 1200 Wh
Total energy per day = 500 + 1200 = 1700 Wh
= 1.7 kWh
Number of days in January = 31 days.
Energy consumed in January = 31 × 1.7 = 52.7 kWh.

Question 3.
A torch bulb is rated at 3 V and 600 mA. Calculate it’s?
(a) power
(b) resistance
(c) energy consumed if it is used for 4 hours.
Solution:
V = 3V and I = 600 mA = 600 × 10^-3 A
(a) Power (P) = VI
= 3 × 600 × 10^-3
= 1800 × 10^-3
= 1.8 W (or) watt.

(b) Resistance (R) = \(\frac{\mathrm{V}}{\mathrm{I}}\) = \(\frac{3}{600 \times 10^{-3}}\) = 5 Ω.

(c) Power (P) = 1.8 W and
Time = 4 hours = 4 × 60 × 60 = 14400 second
Energy consumed E = P × t = 1.8 × 14400 = 25920 joules
E = 25.9 KJ.

Question 4.
A piece of wire having a resistance R is cut into five equal parts.
(a) How will the resistance of each part of the wire change compare with the original resistance?
(b) If the five parts of the wire are placed in parallel, how will the resistance of the combination change?
(c) What will be the ratio of the effective resistance in series connection to that of the parallel connection?
Solution:
(a) Consider a piece of wire having resistance R. It cut into 5 equal parts. So number of equal resistros are 5. n = 5
When ‘n’ resistors of equal resistance R are connected in series, the equivalent resistance is ‘nR’
R_S = nR
⇒ R_S = 5R
⇒ R = \(\frac{\mathrm{R}_{\mathrm{s}}}{5}\)
⇒ R = 0.2 R_S
Each part of resistance ‘R’ is equal to 0.2 times of original resistance.

(b) Effective Resistance of 5 Resistors
\(\frac{1}{\mathrm{R}_{\mathrm{P}}}=\frac{1}{\mathrm{R}}+\frac{1}{\mathrm{R}}+\frac{1}{\mathrm{R}}+\frac{1}{\mathrm{R}}+\frac{1}{\mathrm{R}}\) = \(\frac{5}{\mathrm{R}}\)
\(\mathrm{R}_{\mathrm{P}}=\frac{\mathrm{R}}{5}=0.2 \mathrm{R}\) = 0.2 R.

(c) Effective resistance of series combination R_S = 5R
Effective resistance of parallel combination \(\mathrm{R}_{\mathrm{p}}=\frac{\mathrm{R}}{5}\)
The ratio of series connection to the parallel connection
\(\frac{\mathrm{R}_{\mathrm{s}}}{\mathrm{R}_{\mathrm{p}}}=\frac{5 \mathrm{R}}{(\mathrm{R} / \mathrm{s})}\)
\(\frac{\mathrm{R}_{\mathrm{s}}}{\mathrm{R}_{\mathrm{p}}}=5 \mathrm{R} \times \frac{5}{\mathrm{R}}\) = 25
R_S : R_P = 25 : 1.

XI. HOTS Questions

Question 1.
Two resistors when connected in parallel give the resultant resistance of 2 ohms, but when connected in series the effective resistance becomes 9 ohms. Calculate the value of each resistance.
Solution:
Resultant resistance of parallel combination R_P = 2 Ω
Resultant resistance of series combination R_S = 9 Ω

2(R₁ + R₂) = R₁R₂ ….. (1)
R_S = R₁ + R₂
⇒ 9 = R₁ + R₂
⇒ R₁ = 9 – R₂ ….. (2)
Substitute equation (2) in equation (1)
2(9 – R₂ + R₂) = (9 – R₂) R₂
⇒ \(18=9 \mathrm{R}_{2}-\mathrm{R}_{2}^{2}\)
⇒ \(\mathrm{R}_{2}^{2}-9 \mathrm{R}_{2}+18=0\)
⇒ (R₂ – 3) (R₂ – 6) = 0
⇒ R₂ = 3, 6
(i) If R₂ = 3; R₁ = 9 – R₂ = 9 – 3 = 6 Ω
(ii) If R₂ = 6; R₁ = 9 – R₂ = 9 – 6 = 3 Ω.

Question 2.
How many electrons are passing per second in a circuit in which there is a current of 5 A?
Answer:
A current 10¹⁸ electrons
A current of 5A consists
= 5 × 6.25 × 10¹⁸ electrons = 31.25 × 10¹⁸
Number of electrons passing per second
= 31.25 × 10¹⁸ electrons

Question 3.
A piece of wire of resistance 10 ohms is drawn out so that its length is increased to three times its original length. Calculate the new resistance.
Solution:
Specific resistance (ρ) = \(\frac{\mathrm{RA}}{l}\)
\(\mathrm{R}=\frac{\rho l}{\mathrm{A}}\)
When the length is increased by three and then the area of cross-section is reduced by three,

Samacheer Kalvi 10th Science Electricity Additional Questions

I. Choose the Correct Answer

Question 1.
The motion of electric charges through a conductor will constitute ______.
(a) electric current
(b) electric potential
(c) electric field
(d) none.
Answer:
(a) electric current

Question 2.
Electric charge is expressed in:
(a) Volt
(b) Joule
(c) Coulomb
(d) Ohm
Answer:
(c) Coulomb

Question 3.
A charge of 60 coulomb flows through a bulb in 5 minutes what is the current through the bulb?
(a) 2 A
(b) 0.2 A
(c) 12 A
(d) 0.12 A.
Answer:
(b) 0.2 A
Hint: \(\mathrm{I}=\frac{q}{t}=\frac{60}{5 \times 60}=\frac{1}{5}=0.2 \mathrm{A}\)

Question 4.
1 coulomb of charge is equivalent to the charge of:
(a) 6.25 × 10¹⁸ electrons
(b) 6 × 10¹⁸ protons
(c) 1.6 × 10^-19 electrons
(d) 1.6 × 10^-19 protons
Answer:
(a) 6.25 × 10¹⁸ electrons

Question 5.
The S.I. unit of electric potential difference is ______.
(a) Ampere
(b) Joule
(c) Watt
(d) Volt.
Answer:
(d) Volt

Question 6.
The potential difference V is proportional to the current I, the graph between V and I is a _____.
(a) straight line
(b) parabola
(c) ellipse
(d) none.
Answer:
(a) straight line

Question 7.
In an electric circuit, voltmeter reads 24V and ammeter reads 6A. The value of resistance is:
(a) 40Ω
(b) 2Ω
(c) 0.25Ω
(d) 4Ω
Answer:
(d) 4Ω

Question 8.
What is the potential difference between the ends of a resistor of 15 Ω when a current of 2 A passes through it?
(a) 30 V
(b) 7.5 V
(c) 3 V
(d) 300 V.
Answer:
(a) 30 V

Question 9.
How much heat is generated when current I is passing through a resistor for time t?
(a) I²Rt
(b) IR²t
(c) VI
(d) I²R
Answer:
(a) I²Rt

Question 10.
The unit of conductance is _____.
(a) ohm^-1
(b) volt^-1 ampere
(c) both (a) and (b)
(d) ohm.
Answer:
(c) both (a) and (b)

Question 11.
Two electric bulbs have resistances in the ratio 1 : 2. If they are joined in series, the energy consumed in these are in the ratio:
(a) 1 : 2
(b) 2 : 1
(c) 4 : 1
(d) 1 : 1
Answer:
(a) 1 : 2

Question 12.
The resistance of a wire of length 10 cm is 2 ohm, then its conductance is _____.
(a) 0.5 ohm
(b) 5 ohm^-1
(c) 0.5 ohm^-1
(d) 20 ohm^-1.
Answer:
(c) 0.5 ohm^-1

Question 13.
The value of current flowing through a circuit consisting of two resistance 6Ω and 18Ω in series with a battery of 3 V is:
(a) 0.5 A
(b) 0.125 A
(c) 6 A
(d) 0.25 A
Answer:
(b) 0.125 A

Question 14.
When two 2 Ω resistors are connected in parallel, the effective resistance is _____.
(a) 4 Ω
(b) 1 Ω
(c) 0.5 Ω
(d) 5 Ω.
Answer:
(b) 1 Ω

Question 15.
When two 2 Ω resistors are connected in series, the effective resistance is ______.
(a) 1 Ω
(b) 4 Ω
(c) 5 Ω
(d) 2 Ω.
Answer:
(b) 4 Ω

Question 16.
One kilowatt-hour is:
(a) 3.6 × 10⁶J
(b) 1000 W
(c) 3600 W^-1
(d) 2.778 × 10³ J
Answer:
(a) 3.6 × 10⁶J

Question 17.
When ‘n’ number of resistors are connected in parallel, the effecive resistance for parallel is _____.
(a) nR
(b) \(\frac{n}{\mathrm{R}}\)
(c) \(\frac{\mathbf{R}}{n}\)
(d) none of these.
Answer:
(c) \(\frac{\mathbf{R}}{n}\)

Question 18.
The effective resistance for the given circuit in AB _____.

(a) 1 Ω
(b) 2 Ω
(c) 3 Ω
(d) 1.5 Ω.
Answer:
(d) 1.5 Ω.

Question 19.
The effective resistance between AB in the given circuit _____.

(a) \(\frac{1}{4}\) Ω
(b) \(\frac{1}{2}\) Ω
(c) \(\frac{3}{4}\) Ω
(d) \(\frac{4}{3}\) Ω.
Answer:
(d) \(\frac{4}{3}\) Ω.

Question 20.
The symbol of Ammeter is:
(a) V
(b) A
(c) G
(d) I
Answer:
(b) A

Question 21.
Tungsten material is used in _____.
(a) Fuse wire
(b) bulbs
(c) batteries
(d) none.
Answer:
(b) bulbs

Question 22.
When a charge 24 C flow through a bulb in 10 second then the current flowing through the bulb is:
(a) 1.2 A
(b) 2.4 A
(c) 4.8 A
(d) 0.06 A
Answer:
(b) 2.4 A

Question 23.
The unit of electric power is _____.
(a) Volt-ampere
(b) Watt
(c) both (a) and (b)
(d) only (b).
Answer:
(c) both (a) and (b)

Question 24.
One horsepower is equal to _____.
(a) 764 watt
(b) 746 watt
(c) 647 watt
(d) 674 watt.
Answer:
(b) 746 watt

Question 25.
Unit of specific resistance is:
(a) mho
(b) mho m
(c) ohm m
(d) ampere
Answer:
(c) ohm m

Question 26.
To protect the horse hold electrical appliances from overloading due to excess current _____.
(a) Fuse wire
(b) MCB
(c) both (a) and (b)
(d) none.
Answer:
(c) both (a) and (b)

Question 27.
In India, domestic circuits are supplied with a frequency of ______.
(a) 60 Hz
(b) 50 Hz
(c) 220 Hz
(d) 230 Hz.
Answer:
(b) 50 Hz

Question 28.
What is the unit of conductivity?
(a) ohm m^-1
(b) mho m
(c) ohm m
(d) mho m^-1
Answer:
(d) mho m^-1

Question 29.
The colour of the LED will depend on the type of _____ used.
(a) circuit
(b) materials
(c) display
(d) segment.
Answer:
(b) materials

Question 30.
One way of overcoming the energy crisis is to use more _______ bulbs.
(a) filament
(b) glass
(c) LCD
(d) LED.
Answer:
(d) LED

Question 31.
When resistances are connected in parallel current is more as effective resistance is:
(a) maximum
(b) less
(c) more
(d) minimum
Answer:
(b) less

Question 32.
The current in the electric bulb of 100 W and 200 V electric circuit is _____.
(a) 5 A
(b) 0.5 A
(c) 50 A
(d) 500 A.
Answer:
(b) 0.5 A

II. Fill in the Blanks

Question 1.
Rate of flow of charges in a conductor is _____.
Answer:
electric current.

Question 2.
_____ is used to fix the magnitude of the current through a circuit.
Answer:
Resistor.

Question 3.
______ is used to select the magnitude of the current through a circuit.
Answer:
Rheostat.

Question 4.
_____ is used to measure the current.
Answer:
Ammeter.

Question 5.
______ is used to measure the potential difference.
Answer:
Voltmeter.

Question 6.
______ is used to indicate the direction of the current.
Answer:
Galvanometer.

Question 7.
Electric current passes in the circuit from _____ terminal to the _____ terminal.
Answer:
positive, negative.

Question 8.
Electrical resistivity is _____ for different materials.
Answer:
different.

Question 9.
Reciprocal of resistance is ______.
Answer:
conductance.

Question 10.
Reciprocal of electrical resistivity is ______.
Answer:
electrical conductivity.

Question 11.
The equivalent resistance in a series combination is _____ than the highest of the individual resistances.
Answer:
greater.

Question 12.
The equivalent resistance in a parallel combination is _____ than the lowest of the individual resistances.
Answer:
less.

Question 13.
The heating effect of current is used in devices like _____ and _____.
Answer:
electric heater, electric iron.

Question 14.
Nichrome is an alloy of _____ and _____.
Answer:
Nickel, Chromium.

Question 15.
The filament is made up of a material whose ______ is very high.
Answer:
melting point.

Question 16.
Electric power is the product of _____ and _____.
Answer:
electric current, a potential difference.

Question 17.
The important components of main box are _____ and _____.
Answer:
fuse box, meter.

Question 18.
LED is _____.
Answer:
Light Emitting Diode.

Question 19.
LCD is _____.
Answer:
Liquid Crystal Display.

Question 20.
An array of LEDs act as ______.
Answer:
pixels.

Question 21.
A _____ is the display device used to give an output in the form of _____.
Answer:
Seven Segment display, numbers or text.

III. Match the following.

Question 1.

1. LED	(a) heating device
2. Fuse wire	(b) alloy
3. Tungsten	(c) semiconductor device
4. Nichrome	(d) Filament
5. Electric heater	(e) MCB

Answer:
1. (c) semiconductor device
2. (e) MCB
3. (d) Filament
4. (b) alloy
5. (a) heating device

Question 2.

1. Power	(a) V = IR
2. Joule’s law	(b) \(\rho=\frac{R A}{l}\)
3. Ohm’s law	(c) P = VI
4. Specific Resistance	(d) I = \(\frac { Q }{ t }\)
5. Electric energy	(e) H = I2RT

Answer:
1. (c) P = VI
2. (e) H = I²RT
3. (a) V = IR
4. (b) \(\rho=\frac{R A}{l}\)
5. (e) I = \(\frac { Q }{ t }\)

Question 3.

1. Ammeter	(a) To measure resistance
2. Voltmeter	(b) Direction of current
3. Galvanometer	(c) To measure voltage
4. Ohmmeter	(d) To measure current

Answer:
1. (d) To measure current
2. (c) To measure voltage
3. (b) Direction of current
4. (a) To measure resistance

Question 4.

1. \(\rho=\frac{R A}{l}\)	(a) watt
2. \(\sigma=\frac{1}{\rho}\)	(b) Ωm
3. E = P × t	(c) coulomb
4. P = VI	(d) m-1Ω-1
5. q = It	(e) Kilowatt-hour

Answer:
1. (b) Ω^-1m
2. (d) m^-1Ω^-1
3. (e) Kilowatt-hour
4. (a) watt
5. (c) coulomb

Question 5.

Answer:
1. (c) Resistor
2. (e) Rheostat
3. (b) Voltmeter
4. (a) Ammeter
5. (d) Diode

IV. State whether the following statements are true or false: If false correct the statement.

Question 1.
The equivalent resistance in a series combination in lesser than the highest of the individual resistances.
Answer:
False.
Correct Statement: The equivalent resistance in a series combination is greater than the highest of the individual resistances.

Question 2.
When ‘n’ number of resistors of equal resistance R connected in series, the equivalent resistance is \(\mathrm{R}_{\mathrm{P}}=\frac{\mathrm{R}}{n}\).
Answer:
False.
Correct Statement: R_S = nR.

Question 3.
When resistors are connected in series, a current is less as effective resistance is more.
Answer:
False.
Correct Statement: Current is more as effective resistance is less.

Question 4.
Nichrome is an alloy of copper and chromium.
Answer:
False.
Correct Statement: Nichrome is an alloy of nickel and chromium.

Question 5.
The fuse wire is made up of a material whose melting point is relatively high.
Answer:
False.
Correct Statement: The fuse wire is made up of a material whose melting point is relatively low.

V. Very Short Answer Questions

Question 1.
When a steady current flows in a conductor of non-uniform cross-section will the charge passing per unit time depend on area of cross section of the conductor?
Answer:
No, the charge passing per unit time through the conductor is independent of area of cross-section of the wire.

Question 2.
Name any two – component and give its use?
Answer:

Question 3.
Define the unit of electric potential?
Answer:

1. The SI unit of electric potential or potential difference is volt (V).
2. The potential difference between two points is one volt if one joule of work is done in moving one coulomb of charge from one point to another against the electric force.
   \(1 \text { volt }=\frac{1 \text { joule }}{1 \text { coulomb }}\)

Question 4.
Draw a graph between V and I for a conductor by ohm’s law?
Answer:

Question 5.
What is the relationship between conductance and resistance? State the Unit of conductance.
Answer:
conductance = \(\frac{1}{resistance}\)
G = \(\frac{1}{R}\)
Unit of conductance is mho.

Question 6.
Define the unit of electric power.
Answer:
The SI unit of electric power is watt. When a current of 1 ampere passes across the ends of a conductor, which is at a potential difference of 1 volt, then the electric power is
P = 1 volt × 1 ampere = 1 watt.

Question 7.
Define one kilowatt-hour? Give its value?
Answer:
One kilowatt-hour is otherwise known as one unit of electrical energy. One kilowatt-hour means that electric power of 1000 watt has been utilized for an hour.
1 kWh = 1000 watt-hour = 1000 × (60 × 60) watt-second = 3.6 × 10⁶ J.

Question 8.
Define electric current.
Answer:
Electric current is defined as the rate of flow of charge in a conductor.

VI. Short Answer Questions

Question 1.
Define electrical resistivity? Give its unit.
Answer:
The electrical resistivity of a material is defined as the resistance of a conductor of unit length and unit area of cross – section.
Its unit is ohm metre.

Question 2.
Define specific resistance electrical conductivity? Give its unit.
Answer:
The reciprocal of electrical resistivity of a material is called its electrical conductivity.
\(\sigma=\frac{1}{\rho}\)
Its unit is ohm^-1 metre^-1. It is also represented as mho metre^-1.

Question 3.
Differences between series and parallel circuit?
Answer:

Criteria	Series	Parallel
Equivalent resistance	More than the highest resistance	Less than the lowest resistance
Amount of current	Current is less as effective resistance is more	Current is more as effective resistance is less
Switching ON/OFF	If one appliance is disconnected, others also do not work.	If one appliance is disconnected, others will work independently.

Question 4.
Distinguish electric power and electric energy?
Answer:

Electric Power	Electric Energy
Electric Power is defined as the rate of doing work	It is the capacity to do electric work
P = VI	E = P × t
Unit is watt	Unit is joule (or) [kWh]

Question 5.
Define electric potential difference.
Answer:
The electric potential difference between two points is defined as the amount of work done in moving a unit positive charge from one point to another point against the electric force.

Question 6.
Define Volt.
Answer:
The potential difference between two points is one volt, if one joule of work is done in moving one coulomb of charge from one point to another against the electric force.
1 volt = \(\frac{1joule}{1coulomb}\)

Question 7.
What is the unit of resistance? Define its unit of resistance is ohm.
Answer:
Resistance of a conductor is said to be one ohm if a current of one ampere flows through it when a potential difference of one volt is maintained across its ends.
1 ohm = \(\frac{1volt}{1amphre}\)

VII. Answer in detail.

Question 1.
Explain the series connection of parallel resistors.
Answer:
(i) If we consider the connection of a set of parallel resistors that are connected in series, we get a series – parallel circuit.
(ii) Let R₁ and R₂ be connected in parallel to give an effective resistance of R_P1.
(iii) Similarly, let R₃ and R₄ be connected in parallel to give an effective resistance of R_P2.
(iv) Then, both of these parallel segments are connected in series.


Finally, using the equation the R_S = R₁ + R₂ + R₃ net effecitve resistance is given by R_total = R_P1 + R_P2

Question 2.
Explain the parallel connection of series resistors.
Answer:
(i) Let R₁ and R₂ be connected in parallel to give an effective resistance of R_P1.
(ii) If you consider a connection of a set of series resistors connected in a parallel circuit, we get a parallel-series circuit.
(iii) Let R₁ and R₂ be connected in series to give an effective resistance of R_S1.
(iv) Similarly, let R₃ and R₄ be connected in series to give an effective resistance of R_S2.
(v) Then, both of these serial segments are connected in parallel.

Parallel – Series combination of resistors
Using equation R_S = R₁ + R₂ + R₃ we get
R_S = R₁ + R₂ + R₃
R_S1 = R₁ +R₂
R_S2 = R₃ + R₄
Finally, using equation, \(\frac{1}{\mathrm{R}_{\mathrm{p}}}=\frac{1}{\mathrm{R}_{1}}+\frac{1}{\mathrm{R}_{2}}+\frac{1}{\mathrm{R}_{3}}\) the net effective resistance is given by \(\frac{1}{\mathrm{R}_{\text {total }}}=\frac{1}{\mathrm{R}_{\mathrm{s} 1}}+\frac{1}{\mathrm{R}_{\mathrm{s} 2}}\).

VIII. Numerical Problems

Question 1.
Show that one ampere is equivalent to a flow of 6.25 × 10¹⁸ elementary charges per second.
Solution:
I = 1 A, t = 1 s, e = 1.6 × 10^-19 C
q = ne
\(\mathrm{I}=\frac{q}{t}=\frac{n e}{t}\)
Number of electrons, \(n=\frac{\mathrm{I} t}{e}=\frac{1 \times 1}{1.6 \times 10^{-19}}=6.25 \times 10^{18}\).

Question 2.
How many electrons pass through a lamp in one minute, if the current is 300 mA?
Solution:

Question 3.
Calculate the resistivity of the material of wire 10 m long, 0.4 mm in diameter and having a resistance of 20 Ω.
Solution:
l = 10 m; d = 0.4 mm = 0.4 × 10^-3 m
r = 0.2 × 10^-3 m
R = 20 Ω
Resistivity (or) specific resistance of a material

Question 4.
Find the effective resistance between A and B in the given circuit.
Solution:
Effective resistance in parallel combination 3 Ω and 2 Ω

\(\frac{1}{\mathrm{R}_{\mathrm{p}}}=\frac{1}{\mathrm{R}_{1}}+\frac{1}{\mathrm{R}_{2}}=\frac{1}{3}+\frac{1}{2}=\frac{2+3}{6}=\frac{5}{6} \Omega\)
\(R_{P}=\frac{6}{5}\) = 1.2 Ω

R_S = R₁ + R₂ = 1.2 + 2 = 3.2 Ω.

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You can Download Samacheer Kalvi 10th Maths Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 10th Maths Solutions Chapter 8 Statistics and Probability Additional Questions

Question 1.
Find the standard deviation of 30, 80, 60, 70, 20, 40, 50 using the direct method.
Solution:
Direct method:

Question 2.
Find the standard deviation for the following data. 5, 10, 15, 20, 25. And also find the new
S.D. if three is added to each value.
Solution:



S.D. doesn’t change when a number is added or subtracted to the values.

Question 3.
The marks scored by 5 students in a test for 50 marks are 20, 25, 30, 35, 40. Find the S.D for the marks. If the marks are converted for 100 marks, find the S.D. for newly obtained marks.
Solution:
Let assumed mean A = 30
C = 5


To convert the values for 100, all the values will be multiplied by 2. Therefore the new values are 40, 50, 60, 70, 80.
Let A = 60,
C = 10

S.D. also be multiplied by 2. It is also true for the division also.

Question 4.

Solution:

Question 5.
Find the co-efficient of variation for the following data: 16, 13, 17, 21, 18.
Solution:

Question 6.
C.V. of a data is 69%, S.D. is 15.6, then find its mean.
Solution:

Question 7.
S.D. of a data is 2102, mean is 36.6, then find its C.V.
Solution:

Question 8.

Which team is more consistent?
Solution:




∴ Team A is more consistent.

Question 9.
Final the probability of choosing a spade or a heart card from a deck of cards.
Solution:
Total number of cards = 52
Event of selecting a spade card = A
Event of selecting a heart card = B
n(A) = 13,
n(B) = 13

You can Download Samacheer Kalvi 10th Maths Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 10th Maths Solutions Chapter 8 Statistics and Probability Unit Exercise 8

Question 1.
The mean of the following frequency distribution is 62.8 and the sum of all frequencies is 50. Compute the missing frequencies f₁ and f₂.

Solution:
Mean \(\overline{x}\) = 62.8
\(\Sigma x\) = 50

Question 2.
The diameter of circles (in mm) drawn in a design are given below.

Claculate the standard deviation.
Solution:

Question 3.
The frequency distribution is given below.

In the table, k is a positive integer, has a varience of 160. Determine the value of k.
Solution:

Question 4.
The standard deviation of some temperature data in degree Celsius (°C) is 5. If the data were converted into degree Fahrenheit (°F) then what is the variance?
Answer:
Standard deviation (σ) = 5
Variance = 5² = 25
We know the formula, F = \(\frac{9}{5}\) C + 32
Variance (F) = Vanance \(\frac{9}{5}\) C° + 32
[Variance of ax + b = a² (variance of x)]
= \(\left(\frac{9}{5}\right)^{2}\) . variance
= \(\frac{81}{25}\) × 25
= 81° F
New variance = 81° F

Question 5.
If for a distribution, \(\Sigma(x-5)=3, \Sigma(x-5)^{2}=43\) and total number of observations is 18, find the mean and standard deviation.
Solution:

Question 6.
Prices of peanut packets in various places of two cities are given below. In which city, prices were more stable?

Solution:

Question 7.
If the range and coefficient of range of the data are 20 and 0.2 respectively, then find the largest and smallest values of the data.
Solution:
Range = L – S = 20

Question 8.
If two dice are rolled, then find the probability of getting the product of face value 6 or the difference of face values 5.
Solution:
Product of face values 6: {(1, 6), (2, 3), (6, 1), (3,2)}
Difference of face value 5: {(1, 6), (6, 1)}

Question 9.
In a two children family, find the probability that there is at least one girl in a family.
Solution:
S = {BB, BG, GB, GG}
n(S) = 4
Event of atleast one girl in a family say A
A= {BG, GB, GG}
n( A) = 3

Probability of at least one girl in a family is \(\frac{3}{4}\)

Question 10.
A bag contains 5 white and some black balls. If the probability of drawing a black ball from the bag is twice the probability of drawing a white ball then find the number of black balls.
Solution:
Let a number of black balls be ‘x’.
Number of white balls = 5.

Number of Black balls = 10.

Question 11.
The probability that a student will pass the final examination in both English and Tamil is 0.5 and the probability of passing neither is 0.1. If the probability of passing the English examination is 0.75, what is the probability of passing the Tamil examination?
Solution:

P(English) = 0.75
P(Tamil) = x(assume)
P(English ∪ Tamil) = P(English) + P(Tamil) – P(English ∩ Tamil)
⇒ 1 – 0.1 = 0.75 + x – 0.5
⇒ x = 0.9 – 0.25

Question 12.
The King, Queen and Jack of the suit spade are removed from a deck of 52 cards. One card is selected from the remaining cards. Find the probability of getting
(i) a diamond
(ii) a queen
(iii) a spade
(iv) a heart card bearing the number 5.
Solution:
King spade, Queen spade, Jack spade are removed
∴ total number of cards = 52 – 3 = 49.

You can Download Samacheer Kalvi 10th Maths Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 10th Maths Solutions Chapter 8 Statistics and Probability Ex 8.5

Multiple Choice Questions
Question 1.
Which of the following is not a measure of dispersion?
(1) Range
(2) Standard deviation
(3) Arithmetic mean
(4) Variance
Solution:
(3) Arithmetic mean

Question 2.
The range of the data 8, 8, 8, 8, 8. . . 8 is _____
(1) 0
(2) 1
(3) 8
(4) 3
Answer:
(1) 0
Hint:
Range = L – S = 8 – 8 = 0

Question 3.
The sum of all deviations of the data from its mean is
(1) Always positive
(2) always negative
(3) zero
(4) non-zero integer
Solution:
(3) zero

Question 4.
The mean of 100 observations is 40 and their standard deviation is 3. The sum of squares of all deviations is ______
(1) 40000
(2) 160900
(3) 160000
(4) 30000
Answer:
(2) 160900
Hint:

Question 5.
Variance of the first 20 natural numbers is
(1) 32.25
(2) 44.25
(3) 33.25
(4) 30
Solution:
(3) 33.25

Question 6.
The standard deviation of a data is 3. If each value is multiplied by 5 then the new variance is ______
(1) 3
(2) 15
(3) 5
(4) 225
Answer:
(4) 225
Hint:
Standard deviation = 3
Each value is multiplied by 5
New standard deviation = 3 × 5 = 15
New variance = 152 = 225

Question 7.
If the standard deviation of x, y, z is p then the standard deviation of 3x + 5, 3y + 5, 3z + 5 is
(1) 3p + 5
(2) 3p
(3) p + 5
(4) 9p + 15
Solution:
(2) 3p

Question 8.
If the mean and coefficient of variation of a data are 4 and 87.5% then the standard deviation is _____
(1) 3.5
(2) 3
(3) 4.5
(4) 2.5
Answer:
(1) 3.5
Hint:

Question 9.
Which of the following is incorrect?
(1) P (A) > 1
(2) 0 ≤ P(A) ≤ 1
(3) P(ϕ) = 0 (4)
(4) P (A) + P(\(\overline{\mathbf{A}}\)) = 1
Solution:
(1) P(A) > 1

Question 10.
The probability a red marble selected at random from a jar containing p red, q blue and r green marbles is

Solution:
(2) \(\frac{p}{p+q+r}\)

Question 11.
A page is selected at random from a book. The probability that the digit at units place of the page number chosen is less than 7 is

Solution:
(2) \(\frac{7}{10}\)

Question 12.
The probability of getting a job for a person is \(\frac{x}{3}\). If the probability of not getting the job is \(\frac{2}{3}\) then the value of x is ____
(1) 2
(2) 1
(3) 3
(4) 1.5
Answer:
(2) 1
Hint:

Question 13.
Kamalam went to play a lucky draw contest. 135 tickets of the lucky draw were sold. If the probability of Kamalam winning is \(\frac{1}{9}\), then the number of tickets bought by Kamalam is
(1) 5
(2) 10
(3) 15
(4) 20
Solution:
(3) 15
Hint:
\(=\frac{1}{9} \times 135=15\)

Question 14.
If a letter is chosen at random from the English alphabets {a, b, ……, z} then the probability that the letter chosen precedes x _______
(1) \(\frac{12}{13}\)
(2) \(\frac{1}{13}\)
(3) \(\frac{23}{26}\)
(4) \(\frac{3}{26}\)
Answer:
(3) \(\frac{23}{26}\)
Hint:

Question 15.
A purse contains 10 notes of ₹ 2000, 15 notes of ₹ 500, and 25 notes of ₹ 200. One note is drawn at random. What is the probability that the note is either a ₹ 500 note or ₹ 200 note?
(1) \(\frac{1}{5}\)
(2) \(\frac{3}{10}\)
(3) \(\frac{2}{3}\)
(4) \(\frac{4}{5}\)
Solution:
(4) \(\frac{4}{5}\)