wave_mechanics dopplers_effect Question 46

Question: A source and an observer move away from each other with a velocity of 10 m/s with respect to ground. If the observer finds the frequency of sound coming from the source as 1950 Hz, then actual frequency of the source is (velocity of sound in air = 340 m/s)

[EAMCET 1997; MH CET 2000; AFMC 2000; CBSE PMT 2001]

Options:

A) 1950 Hz

B) 2068 Hz

C) 2132 Hz

D) 2486 Hz

Show Answer

Answer:

Correct Answer: B

Solution:

$ {n}’=n( \frac{v-v _{O}}{v+v _{S}} )=n( \frac{340-10}{340+10} )=1950 $

$ \Rightarrow $ $ n=2068 $

$ Hz $