Sound Class 9

Sound – Class 9 (MCQs)

1. Sound is produced due to the ________ of an object.

a) motion

b) vibration

c) rotation

d) friction

2. Sound cannot travel through:

a) air

b) water

c) iron

d) vacuum

3. The unit of frequency is:

a) decibel

b) metre

c) hertz

d) second

4. The time taken to complete one oscillation is called:

a) frequency

b) amplitude

c) time period

d) wavelength

5. The loudness of sound depends upon its:

a) frequency

b) speed

c) amplitude

d) wavelength

6. The pitch of sound depends on its:

a) amplitude

b) speed

c) frequency

d) density

7. Which of the following sound has the highest frequency?

a) Infrasonic sound

b) Audible sound

c) Ultrasonic sound

d) Musical sound

8. Sound travels fastest in:

a) gases

b) liquids

c) solids

d) vacuum

9. The sound which has frequency less than 20 Hz is called:

a) audible sound

b) ultrasonic sound

c) infrasonic sound

d) echo

10. The speed of sound in air at room temperature is approximately:

a) 150 m/s

b) 330 m/s

c) 1000 m/s

d) 3000 m/s

11. Which characteristic of sound helps us to differentiate between sounds from different sources having the same loudness and pitch?

a) loudness

b) pitch

c) quality (timbre)

d) frequency

12. Echo is heard when the reflected sound reaches the ear after:

a) 0.01 s

b) 0.05 s

c) 0.1 s

d) 1 s

13. The minimum distance between the source of sound and reflecting surface for echo to be heard is about:

a) 5 m

b) 10 m

c) 17 m

d) 34 m

14. Which of the following is used by bats for navigation?

a) echo

b) refraction

c) diffraction

d) interference

15. The number of vibrations completed in one second is called:

a) time period

b) frequency

c) amplitude

d) wavelength

16. The sound level is measured in:

a) hertz

b) watt

c) joule

d) decibel

17. A person produces sound louder by:

a) increasing frequency

b) increasing amplitude

c) increasing time period

d) decreasing wavelength

18. The SI unit of time period is:

a) hertz

b) metre

c) second

d) decibel

19. Which part of the human ear vibrates when sound waves strike it?

a) cochlea

b) auditory nerve

c) eardrum

d) ear ossicles

20. The phenomen

on due to which sound persists in a hall even after the source has stopped is called:

a) echo

b) reflection

c) reverberation

d) resonance