Question

When both source and listener move in the same direction with a velocity equal to half the velocity of sound, the change in frequency of the sound as detected by the listener is :

• A. 50%
• B. 25%
• C. zero
• D. none of these

Answer 1

The correct option is C zero

$f^{\prime }=\frac{v+v_o}{v+v_s}f$ ,
if $v_o=v_s$ then $f^{\prime }=f$
option "C" is correct.