CBSE Class 8 Science Sound Assignment Set A

Sound

Speed of sound = v = 440 m/s

More Question

I. Fill in the blanks.

1. To and fro or back and forth motion of an object is called ___________.

2. In humans the sound is produced by the ________ or the ___________.

3. ________ are stretched across the voice box or larynx.

4. The vocal cords in men are about ______ mm long.

5. Noise becomes physically painful at _____ dB.

6. Frequency determines the ________ of a sound.

7. ________ on the roadside and elsewhere can reduce noise pollution.

8. _________ and _______ are two important properties of sound.

9. ________ senses the vibrations of sound.

II. Name the following

1. An instrument used for investigating and tracking many medical problems.

2. Name the major causes of noise pollution.

3. Name the sources in home which may lead to noise.

4. Give examples of objects which produce sounds of low frequency or low pitched.

5. Give examples of objects which produce sound of high frequency or high pitched.

Some Natural Phenomena

Q1. What type of electric charge is acquired by a rubber balloon when rubbed with a woolen cloth?

Q2. A positively charged object repels another charged object kept close to it. What is the nature of charge on the other object?

Q3. A glass rod is rubbed with a silk cloth & a rubber balloon is rubbed with a woolen cloth.

a) Which two objects acquire negative charge?

b) Which two objects acquire positive charge?

Q4. Explain why, a glass rod can be charged by rubbing when held by hand but an iron rod cannot be charged by rubbing, if held by hand?

Q5. Consider three charged bodies P, Q & R. If P & Q repel each other & P attracts R. What is the nature of force between Q & R?

Q6. Name the device used to detect electric charge on a body. Draw its labeled diagram.

Q7. What will you observe when the metal cap of an electroscope is touched with a glass rod which has been rubbed with silk cloth? Give reason for your answer.

Q8. What are the uses of an electroscope? (3 points)

Q9. Why do the leaves of a gold leaf electroscope diverge when a charged body is brought in contact with its disc?

Q10. Do the leaves of an electroscope always diverge to the same extent when a charged body is brought in contact with its disc?

Q11. What will you observe when the metal cap of an electroscope is touched with:

a) A positively charged object?

b) A negatively charged object?

Click on link below to download CBSE Class 8 Science Sound Assignment Set A