Q14 of 118 Page 351

The engine of a train sounds a whistle at frequency v. The frequency heard by a passenger is

Since the source and the observer both move with the same speed there is no relative motion. Thus there is no Doppler's effect and no change in apparent frequency. Hence the option D is correct.

More from this chapter

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12

The phenomenon of beats can take place

 13

A tuning fork of frequency 512 Hz is vibrated with a sonometer wire and 6 beats per second are heard. The beat frequency reduces if the tension in the string is slightly increased. The original frequency of vibration of the string is

 15

The change in frequency due to Doppler effect does not depend on

A. the speed of the source


B. the speed of the observer


C. the frequency of the source


D. separation between the source and the observer


 16

A small source of sound moves on a circle as shown in figure (16-Q1) and an observer is sitting at O. Let v1, v2, v3 be the frequencies heard when the source is at A, B and C respectively.