Physics

1. A student sees a jet plane flying from east to west. When the jet is seen just above his head, the sound of jet appears to reach him making angle 60° with the horizontal from east. If the velocity of sound is c, then that of the jet plane is:

C/2

√3/2 c

2 c

2/√3 c

Question 1 of 25

2. When both source and listener move in the same direction with a velocity equal to half the velocity of sound, the change in frequency of the sound as detected by the listener is:

Zero

25%

50%

None of these

Question 2 of 25

3. Velocity of sound in air at the given temperature:

May increase on decrease with pressure

Decreases with increase in pressure

Varies directly as the square root of pressure

Is independent of the variation in pressure

Question 3 of 25

4. The wavelength of light received from a galaxy is 10% greatest than that received from identical source on the earth. The velocity of the galaxy relative to the earth is:

3 * 105 ms-1

3 * 107 ms-1

3 * 108 ms-1

3 * 106 ms-1

Question 4 of 25

5. The difference between the apparent frequency of sound that is heard by the stationary listener, when the source approaches and then recedes with the same velocity is 5% of the natural frequency. Given that the velocity of sound is 320 ms^-1, the velocity of the source is:

10 ms-1

12 ms-1

4 ms-1

8 ms-1

Question 5 of 25

6. Under similar conditions of temperature and pressure, in which of the following gases the velocity of sound will be the largest?

CO2

Question 6 of 25

7. A train is approaching the platform with a speed of 4 ms^-1. Another train is leaving the platform with the same speed. The velocity of sound is 320 ms^-1. If both the trains sound their whistles at frequency 280 hertz, the number of beats heard per second will be:

Question 7 of 25

8. The velocity of sound in oxygen at NTP is v. The velocity of sound in helium at NTP should be:

2 √2

2 v

4 v

None of these

Question 8 of 25

9. A car sounding its horn at 480 Hz moves toward a high wall at a speed of 20 ms^-1. If the speed of the sound is 340 ms^-1, the frequency of the reflected sound heard by the passenger sitting in the car will be nearest to:

610 Hz

570 Hz

480 Hz

540 Hz

Question 9 of 25

10. When both source and listerner approach each other with a velocity equal to half the velocity of sound, the change in frequency of the sound as detected by the listener is:

None of these

Zero

25%

50%

Question 10 of 25

11. The velocity of sound in oxygen at NTP is v. The velocity of sound in hydrogen at NTP will be:

4 v

2 v

2 √2

None of these

Question 11 of 25

12. The velocity of sound at 0 °C is 332 ms^-1. At what temperature will it be 664 ms^-1?

819 °C

273 °C

1092 °C

546 °C

Question 12 of 25

13. Two factories are sounding their sirens at 800 Hz. A man goes from one factory to other at a speed of 2 ms^-1. The velocity of sound is 320 ms^-1. The number of beats heard by the person in one second will be:

Question 13 of 25

14. Radio waves of wavelength λ are sent from a radar towards an aeroplane. If the aeroplane is moving towards the radar station, the wavelength of the radiowaves, received after the reflection from the aeroplane will be:

More than λ

More or less than λ, depending on the speed of aeroplane

Less than λ

Question 14 of 25

15. A source of sound moves towards a stationary listener. The apparent pitch of the sound is found to be higher than its actual value. This happens because:

The number of waves received by the listener increases

The number of waves received by the listener decreases

Wavelength of sound waves decreases

Wavelength of sound waves increases

Question 15 of 25

16. The wavelength of the sound produced by a source is 0.8 m. If the source moves towards the stationary listener at 32 ms¹, what will be apparent wavelength of the sound? The velocity of sound is 320 ms^-1?

0.32 m

0.80 m

0.72 m

0.40 m

Question 16 of 25

17. In which one of the following cases the jet aerolane is flying at supersonic speed?

Its sound makes 30° with the vertical, when the jet is passing over the head of the listener

line of sight makes 60° with the vertical, when sound appears to be coming vertically downwards

Its line of sight makes 30° with the vertical when sound appears to be coming vertically downwards

Its sound makes 60° with the vertical, when sound appears to be coming vertically downwards

Question 17 of 25

18. The velocity of sound in air is 330 ms^-1. To increase the apparent frequency of the sound by 50%, the source should move towards the stationary observer with a velocity equal to:

165 ms-1

330ms-1

110 ms-1

220 ms-1

Question 18 of 25

19. If tension is the string is increased from 1 kN to 4kN, other factors remaining unchanged, the frequency of the second harmonic will:

Be halved

Become four times

Be doubled

Remain unchanged

Question 19 of 25

20. A source of sound is moving towards a high wall with a speed of 20 ms^-1. The frequency of the sound produced by the source is 400 Hz. If the sound travels at 340 ms^-1, what will be the beat frequency heard by a man standing near the wall?

Zero

Question 20 of 25

21. The sound of minimum frequency emitted by a vibrating string is not termed as:

None of these

First harmonic

Fundamental tone

First overtone

Question 21 of 25

22. The velocity of sound is 330 ms^-1. To hear a sound with 50% higher frequency, a listener should move towards the stationary source with a velocity equal to:

110 ms-1

220 ms-1

330 ms-1

165 ms-1

Question 22 of 25

23. A person hears the sound of jet aeroplane after it has passed over his head. The angle of the jet plane with the horizontal when the sound appears to be coming vertically downwards in 60 °. If the velocity of the sound is c, then the velocity of the jet plane should be:

√3 c

c/√3

2 c

Question 23 of 25

24. The pitch of the sound as detected by the observer is independent of:

Relative velocity of source and observer

The velocity of sound in the medium

Original frequency

None of these factors

Question 24 of 25

25. In case of vibrating string, the frequency of the first overtone is equal to frequency of the:

Fundamental note

First harmonic

Second harmonic

None of these

Question 25 of 25

Test Name	Wave Motion MCQs Test
Subject	Physics
Test Type	MCQs
Total Question	25
Total Marks	50
Total Time	20 Mints
Test Help For	Physics Subject Test Prep. Engineering and BDS Tes Prep. Medical Exams Prep. All Admissions Test. All Jobs Test prep.

Test By Subject	Physics
Test By Topics	Physics Subject

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Physics Wave Motion Test Online MCQs

Physics Wave Motion Test Online MCQs

Physics

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