Question

A train with a frequency ‘f’. What will be the frequency heard by a person sitting in the train? Speed of the train is ‘v’.

(a) f

(b) f(330+v)/330

(c) fv/(330-v)

(d) fv/(330+v)

This question was addressed to me during an interview for a job.

My question is taken from Waves in chapter Waves of Physics – Class 11

Answer 1

Right choice is (a) f

To elaborate: There is no relative motion between the source and observer, thus the frequency heard by the person will be the original frequency of the whistle.