JEE PHYSICS MCQ: WAVE OPTICS

1 Medium

1 of 1

Analyzing +4 | -1

A sound wave of frequency

f

travelling horizontally to the right is reflected by a large vertical plane surface moving to left with a speed

v

. There is a detector (1) attached on the surface and another detector (2) fixed on ground. If the speed of sound in the medium is

c

, then the difference in the frequency received by detector 2 after being reflected from the surface and the frequency received by detector 1 is

View answer and explanation

Correct option: D

\Delta f=f\left[\frac{v(c+v)}{c(c-v)}\right]

Option D (

\Delta f=f\left[\frac{v(c+v)}{c(c-v)}\right]

) is correct because it correctly applies the Doppler effect twice: once for the wave hitting the moving surface and again for the reflected wave reaching the stationary detector.

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