Physics Wave Motion Test Online MCQs

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

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

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

4. 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:

5. 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:

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

7. 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?

8. 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:

9. 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:

10. 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:

11. 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?

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

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

14. 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:

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

16. 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:

17. 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:

18. 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:

19. 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:

20. 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:

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

22. 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:

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

24. 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:

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