Question

A source of sound and a detector are moving along the same line with same speed :

• A. frequency registered by the detector is same as frequency of source
• B. frequency registered by the detector is same as frequency of source if source is ahead
• C. frequency registered by the detector is same as frequency of source if detector is ahead
• D. no sound is received by the detector

Answer 1

The correct option is A frequency registered by the detector is same as frequency of source

$F=(\frac{V+V_o}{V+V_s})f_0$

$Vs=V_o$

$\therefore f=f_o$

$V=$ velocity of sound

$V_s=$velocity of the source

$V_o=$ velocity of the observer