Question

A stationary source producing a sound of frequency $900\text{Hz}$. What will be the frequency of the sound heard by the listener revolving around the source with a uniform velocity of $8{\text{m s}}^{-1}$? (velocity of sound is $350{\text{m s}}^{-1}$)

• A. $920\text{Hz}$
• B. $880\text{Hz}$
• C. $900\text{Hz}$
• D. $0\text{Hz}$

Answer 1

The correct option is C $900\text{Hz}$

Doppler effect is not seen in case of uniform circular motion. Since the listener is moving around the source with uniform velocity, the frequency and the velocity of the sound emitted by the source do not matter; the frequency of the sound perceived by the listener will be the same as that emitted by the source.

Therefore, the frequency of the sound heard by the listener $=900\text{Hz}$