wave_mechanics critical_thinking Question 17
Question: An observer moves towards a stationary source of sound with a speed 1/5th of the speed of sound. The wavelength and frequency of the source emitted are $ \lambda $ and $ f $ respectively. The apparent frequency and wavelength recorded by the observer are respectively
[CBSE PMT 2003]
Options:
A) $ 1.2\ f,\ \lambda $
B) $ f,\ 1.2\lambda $
C) $ 0.8f,\ 0.8\lambda $
D) $ 1.2f,\ 1.2\lambda $
Show Answer
Answer:
Correct Answer: A
Solution:
$ n’=\frac{v+v _{0}}{v}.n=\frac{v+\frac{v}{5}}{v}.f=\frac{6}{5}f=1.2f $ and since the source is stationary, so wave length remains unchanged for observer.
BETA
