Question

Doppler effect is not seen when the source and the listener are

• A. at rest
• B. moving with different velocities
• C. moving with the same velocity
• D. (a) and (c) above.

Answer 1

The correct option is D (a) and (c) above.

There will be no Doppler effect and the apparent frequency as heard by the listener will be the same as the source frequency, when:

• When both the source and the listener are at rest.
• When they move in such a way that distance between them remains constant, i.e. their velocity is the same.
• When they are travelling in mutually perpendicular directions.
• When one of them is in uniform circular motion w.r.t the other.