Q. An observer is moving away from source of sound of frequency $100\ Hz.$ This speed is $33\ m/s.$ If speed of sound is $330\ m/s,$ then the observed frequency is
A) $90\ Hz$
B) $100\ Hz$
C) $91\ Hz$
D) $110\ Hz$
Explanation
(a) $n^{'} = n\left( \frac{v - v_{O}}{v} \right) = \left( \frac{330 - 33}{330} \right) \times 100 = 90\ Hz$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.