Q. What should be the velocity of a sound source moving towards a stationary observer so that apparent frequency is double the actual frequency (Velocity of sound is $v$)
A) $v$
B) $2v$
C) $\frac{v}{2}$
D) $\frac{v}{4}$
Explanation
(c) By using $
$$n^{'} = \left( \frac{v}{v - v_{S}} \right) \Rightarrow 2n = n\left( \frac{v}{v - v_{S}} \right) \Rightarrow v_{S} = \frac{v}{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.