# MCQ Questions for Class 9 Science Chapter 12 Sound

MCQ Questions for Class 9 Science Chapter 12 Sound will fulfil the needs of every student and speed up their learning process. It can be used to measure a student’s progress over time and identify areas where further study is required.

These questions can provide a quick way to check understanding and identify any areas that may need more revision. Chapter 12 Class 9 Science CBSE MCQ Questions with answers can help you identify what you know and what you need to work on.

## Chapter 12 Sound Class 9 Science MCQ Questions

1. The change in density/pressure of a medium from maximum value to minimum value and again to maximum value, due to the propagation of a longitudinal wave is called a complete
(a) oscillation
(b) frequency
(c) amplitude
(d) none of these
▶ (a) oscillation

2. Sound travels in air if
(а) particles of medium travel from one place to another
(b) there is no moisture in the atmosphere
(c) disturbance moves
(d) both particles as well as disturbance travel from one place to another
▶ (d) both particles as well as disturbance travel from one place to another

3. An instrument commonly used in laboratory to produce a sound of some particular frequency is
(a) sonar
(b) electric bell
(c) tuning fork
(d) a stretched wire
▶ (c) tuning fork

4. In case of transverse waves, the particles of a medium vibrate
(a) in the direction of wave propagation
(b) opposite to the direction of wave propagation
(c) at the right angles to the direction of wave propagation
(d) none of these
▶ (c) at the right angles to the direction of wave propagation

5. Earthquake produces which kind of sound before the main shock wave begins
(a) ultrasound
(b) infrasound
(c) audible sound
(d) none of the above
▶ (a) ultrasound

6. Non-mechanical wave can travel
(a) in vacuum as well as in a medium
(b) in vacuum but not in a medium
(c) in medium but not in vacuum
(d) neither in a medium nor in vacuum
▶ (a) in vacuum as well as in a medium

7. Sound travels at a speed of 334 m s-1 in air. This means that
(a) the source of sound moves 334 m in one second
(b) the listener moves 334 m in one second
(c) air moves 334 m in one second
(d) the disturbance in air moves 334 m in one second
▶ (d) the disturbance in air moves 334 m in one second

8. When a sound wave travels in air, the physical quantity which is transferred from one place to the other is
(a) mass
(b) force
(c) air particle
(d) energy
▶ (d) energy

9. The vibrations in the ear are amplified by
(a) hammer
(b) anvil
(c) stirrup
(d) all of these
▶ (d) all of these

10. Human ear cannot hear those mechanical waves whose frequency lies in the frequency range
(a) less than 100 Hz but greater than 10000 Hz
(b) between 1000 Hz and 5000 Hz
(c) between 500 Hz and 20000 Hz
(d) less than 20 Hz and more than 20000 Hz
▶ (d) less than 20 Hz and more than 20000 Hz

11. If the density of air at a point through which a sound wave is passing is maximum at an instant, the pressure at that point will be
(a) minimum
(b) same as the density of air
(c) equal to the atmospheric pressure
(d) maximum
▶ (d) maximum

12. Water waves are
(a) longitudinal
(b) transverse
(c) Both longitudinal and transverse
(d) neither longitudinal nor transverse
▶ (c) Both longitudinal and transverse

13. Which of the following is an elastic wave?
(a) Sound waves
(b) Light waves
(c) X-rays
▶ (a) Sound waves

14. When we change feeble sound to loud sound we increase its
(a) frequency
(b) amplitude
(c) velocity
(d) wavelength
▶ (b) amplitude

15. An object moving at a speed greater than that of sound is said to be moving at
(a) ultrasonic speed
(b) sonic speed
(c) infrasonic speed
(d) supersonic speed
▶ (d) supersonic speed

16. In inner ear, the pressure variations are turned into electrical signals by
(a) Oval window
(b) Cochlea
(c) Auditory canal
(d) Eardrum
▶ (b) Cochlea

17. Which of the following statements are correct?
(a) Sound is a form of energy which produces a sensation of hearing in our ears.
(b) Sound cannot be produced without utilizing energy.
(c) Vibrating objects produce sound.
(d) All of these
▶ (d) All of these

18. Sound waves and light waves are similar in that both
(a) are produced by mechanical vibrations
(b) are longitudinal waves
(c) can travel through vacuum
(d) obey the laws of reflection
▶ (d) obey the laws of reflection

19. An object moving at a speed greater than that of sound is said to be moving at
(a) ultrasonic speed
(b) sonic speed
(c) infrasonic speed
(d) supersonic speed
▶ (d) supersonic speed

20. In case of longitudinal waves, the particles of medium vibrate
(a) in the direction of wave propagation
(b) opposite to the direction of wave propagation
(c) at right angles to the direction of wave propagation.
(d) none of the above
▶ (a) in the direction of wave propagation

21. If you go on increasing the stretching force on a wire in a guitar, its frequency
(a) increases
(b) decreases
(c) remains unchanged
(d) none of these
▶ (a) increases

22. Mechanical wave can travel
(a) in vacuum as well as in a medium
(b) in vacuum but not in a medium
(c) in a medium but not in vacuum
(d) neither in a medium nor in vacuum
▶ (c) in a medium but not in vacuum

23. Two waves of sinusoidal waveforms are same wavelengths and different amplitude. They will be having
(a) same pitch and different intensity
(b) same quality and different intensity
(c) different quality and different intensity
(d) same quality and different pitch
▶ (a) same pitch and different intensity

24. In the region of compression or rarefaction, in a longitudinal wave the physical quantity which does not change is
(a) pressure
(b) mass
(c) density
(d) volume
▶ (b) mass

25. Which of the following changes when sound is reflected?
(a) Wavelength
(b) Frequency
(c) Speed
(d) Amplitude
▶ (d) Amplitude

26. The eardrum is a
(a) bone
(b) fluid
(c) coiled tube
(d) a stretched membrane
▶ (d) a stretched membrane