wave_mechanics dopplers_effect Question 55

Question: A source and an observer approach each other with same velocity 50 m/s. If the apparent frequency is 435 sec?1, then the real frequency is

[CPMT 2003]

Options:

A) 320 s?1

B) 360 sec?1

C) 390 sec?1

D) 420 sec?1

Show Answer

Answer:

Correct Answer: A

Solution:

$ n’=n[ \frac{v+v _{O}}{v-v _{S}} ]; $ Here $ v=332 $ m/s and $ v _{0}=v _{s}=50 $ m/s $ \Rightarrow $ $ 435=n[ \frac{332+50}{332-50} ]\Rightarrow n=321.12se{{c}^{-1}}\approx 320sec^{1} $