Q. A source of sound is travelling towards a stationary observer. The frequency of sound heard by the observer is of three times the original frequency. The velocity of sound is $v\ m/sec.$ The speed of source will be
A) $\frac{2}{3}v$
B) $v$
C) $\frac{3}{2}v$
D) $3v$
Explanation
(a) $n^{'} = n\left( \frac{v}{v - v_{S}} \right) \Rightarrow \frac{n^{'}}{n} = \frac{v}{v - v_{S}} \Rightarrow \frac{v}{v - v_{S}} = 3 \Rightarrow v_{s} = \frac{2v}{3}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.