Acoustics MCQs Industries Extension officer: Industries Extension officer Exam, Kerala PSC is scheduled on 18 Feb 2025. This post will help you in revising the topic Acoustics in Engineering Physics.
1. Choose the correct answer out of following.
(a) Speed of sound waves is constant in vacuum
(b) Speed of sound waves is dense medium is greater than rare medium
(c) Speed of sound waves is rare medium is greater than dense medium
(d) Speed of sound in any medium is independent of temperature
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2. What is the frequency range of sound auditable to humans?
(a) 20 kHz to 20 MHz
(b) 20 Hz to 20 MHz
(c) 20 Hz to 20 kHz
(d) 20 kHz to 20 GHz
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3. What is true regarding the speed of sound in vacuum?
(a) Speed of sound in vacuum is a constant quantity
(b) Speed of sound in vacuum is variable
(c) Speed of sound is equal to speed of light in vacuum
(d) Sound cannot travel in vacuum
4. When sound travels through air, the air particles ______.
(a) vibrate along the direction of wave propagation
(b) vibrate but not in any fixed direction
(c) vibrate perpendicular to the direction of wave propagation
(d) do not vibrate
5. Sound waves do not travel through
(a) Solids
(b) Liquids
(c) Gases
(d) Vacuum
6. Sound waves are
(a) Transverse
(b) Longitudinal
(c) Partly longitudinal and partly transverse
(d) Sometimes longitudinal and sometimes transverse
7. The frequency which is not audible to the human ear is
(a) 50 Hz
(b) 500 Hz
(c) 5000 Hz
(d) 50000 Hz
8. The speed of sound in medium depends upon
(a) Properties of the medium
(b) Amplitude
(c) Frequency
(d) Wavelength
9. Which of the following will remain unchanged when a sound wave travels in
air or in water?
(a) Amplitude (b) Wavelength
(c) Frequency (d) Speed
10. Sound and light waves both
(a) have similar wavelength in vacuum
(b) obey the laws of reflection
(c) travel as longitudinal waves
(d) travel through vacuum
11. Which of the following quantities is transferred during wave propagation?
(a) Speed
(b) Mass
(c) Matter
(d) Energy
12. The relation between wave velocity ‘v’, frequency ‘f ‘, and wavelength ‘l’ is ___
(a) v = f / ฮป
(b) v = ฮป / f
(c) v = f ฮป
(d) v = 1/ฮปf
13. A sound source sends waves of 400 Hz. It produces waves of wavelength 2.5
m. The velocity of sound waves is
(a) 100 m/s
(b) 1000 m/s
(c) 10000 m/s
(d) 3000 km/s
14. Sound waves shows which of following properties d
(a) Reflection
(b) Refraction
(c) Diffraction
(d) All of above
15. Sound waves do not show which of the following properties? c
(a) Interference
(b) Diffraction
(c) Polarization
(d) Refraction
16. The number of vibrations of the particles of a medium through which sound b
wave travels in one second is known as
(a) Wave velocity
ย (b) Frequency
(c) Time period
(d) One wave
17. The time required by a particle in a medium through which sound wave is a
traveling to complete one vibration is
(a) Time period
(b) Frequency
(c) Amplitude
(d) Wavelength
18. The distance traveled by a sound wave in one time period is _________ a
(a) Wavelength
(b) Amplitude
(c) Velocity
(d) Intensity
19. The maximum displacement of a particle of the medium through which sound
is traveling is b
(a) Wavelength
(b) Amplitude
(c) Velocity
(d) Displacement
20. Wavelength of sound is d
(a) Distance traveled by the sound wave during one vibration of a particle
(b) Distance between two adjacent compressions
(c) Distance between two adjacent rarefaction
(d) All the above
21. A sound wave of wavelength 10 cm traveling with a speed of 340 m/s has c
frequency of
(a) 34 Hz
(b) 340 Hz
(c) 3400 Hz
(d) 1/34 Hz
22. A sound wave of wavelength 10 cm traveling with a speed of 340 m/s has time
period b
(a) 1/34 s
(b) 1/3400 s
(c) 3400 s
(d) 34 s
23. The distance traveled by sound wave of frequency 3.4 kHz traveling with a b
speed of 340 m/s in one time period is ________ m
(a) 100
(b) 10
(c) 1
(d) 0.1
24. The amplitude of sound wave of frequency 3.4 kHz traveling with a speed of
340 m/s is ______ d
(a) 100
(b) 1/100
(c) 1
(d) None of above
25. When a sound wave of wavelength 10 cm travels with a speed of 340 m/s the c
particles of the medium vibrate at the rate of _______ vibrations per second
(a) 34
(b) 340
(c) 3400
(d) 1/34
26. When a sound wave of wavelength 10 cm travels with a speed of 340 m/s the b
particles of the medium take _____ seconds to complete one vibration
(a) 1/34
(b) 1/3400
(c) 3400
(d) 34
27. A sound wave of wavelength 10 cm traveling with a speed of 340 m/s covers a
distance in one second c
(a) 1
(b) 34
(c) 340
(d) 3400
28. What happens when a sound incidents over a surface? d
(a) All the sound energy is
reflected
(b) All the sound energy is absorbed
(c) All the sound energy is transmitted
(d) Partial absorption, partial reflection and partly transmission of sound energy
29. Which of the following quantities is transferred during wave propagation? a
(a) Energy
(b) Speed
(c) Mass
(d) Matter
30. A sound vibrator is making 100 vibrations in one second. The frequency of sound produced is
(a) 3400 Hz
(b) 340 Hz
(c) 100 Hz
(d) 1000 Hz
31. Sound waves of frequency less than 20 Hz is known as c
(a) Ultrasonic
(b) Audible
(c) Infrasonic
(d) Supersonic
32. Sound waves of frequency more than 20 kHz are known as a
(a) Ultrasonic
(b) Audible
(c) Infrasonic
(d) Supersonic
33. Speed exceeding the speed of sound is known as d
(a) Ultrasonic
(b) Audible
(c) Infrasonic
(d) Supersonic
34. How the speed of sound wave depends on temperature of the medium? c
(a) It decreases with increase in the temperature of the medium
(b) Speed of sound does not depend on temperature
ย (c) It increases with increase in the temperature of the medium
(d) Speed of sound increases and decreases alternately
35. Loudness of sound depends upon c
(a) Intensity of sound
(b) Sensitivity of ear
(c) Both intensity of sound and sensitivity of ear
(d) None of above
36. The amount of sound energy flowing per unit area per unit time is known as a
(a) Intensity
(b) Loudness
(c) Pitch
(d) Timbre
37. The unit of intensity of sound is d
(a) Bel
(b) Decibel
(c) W/m
(d) W/m2
38. The smallest intensity of sound that human ear can detect is known as b
(a) Critical intensity
(b) Threshold intensity
(c) Minimum intensity
(d) Zero intensity
39. According to Weber-Fechner law, the loudness of sound is c
(a) Proportional to intensity level
(b) Inversely proportional to intensity level
(c) Proportional to logarithm of intensity level
(d) Inversely proportional to logarithm of intensity level
40. Bel and/or Decibel is a unit of which quantity for sound? a
(a) Loudness
(b) Intensity
(c) Frequency
(d) Quality
41. Higher frequency sound is said to have higher b
(a) Loudness
(b) Pitch
(c) Timbre
(d) Intensity
42. Musical instruments have higher
(a) Loudness
(b) Pitch
(c) Timbre
(d) Intensity
43. Timbre enables us to distinguish two sounds of c
(a) Different intensities
(b) Different frequencies
(c) Same frequencies
(d) Different wavelengths
44. Presence of overtone in sound decides its a
(a) Quality
(b) Pitch
(c) Loudness
(d) Intensity
45. Quality of sound is because of
(a) Frequency
(b) Overtones
(c) Wavelength
(d) Intensity
46. The fundamental frequency of sound decides its
(a) Timbre
(b) Loudness
(c) Intensity level
(d) Pitch
47. Intensity level of sound decides its a
(a) Loudness
(b) Pitch
(c) Timbre
(d) None of these
48. Assuming the speed of sound in air as 340 m/s, a person receives an echo from a well after 0.2 seconds. What would be depth of the well?
(a) 20 m
(b) 34 m
(c) 40 m
(d) 50 m
49. Assuming the speed of sound in air as 340 m/s, a person receives an echo from a hill after 1 second. What would be the distance of the hill from the person?
(a) 1700 m
(b) 170 m
(c) 340 m
(d) 3400 m
50. When size of the obstacle in the path of sound is small compared to its
Wavelength which of the following effects will be observed?
(a) Interference of sound
(b) Diffraction of sound
(c) Reflection of sound
(d) Polarization of sound
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