An observer moves towards a stationary source of sound, with a velocity one-fifth of the velocity of sound. What is the percentage increase in the apparent frequency?

Question

An observer moves towards a stationary source of sound, with a velocity one-fifth of the velocity of sound. What is the percentage increase in the apparent frequency? (A) 5 % (B) 20 % (C) 0 % (D) 0.5 %

Tardigrade Admin · Accepted Answer

fapp=f0((v + v0/v)) (fapp - f0/f0)=(v0/v)=((v/5)/v)=(1/5)=20 %

Q. An observer moves towards a stationary source of sound, with a velocity one-fifth of the velocity of sound. What is the percentage increase in the apparent frequency?

$5%$

$20%$

$0%$

$0.5%$

$f_{a pp} = f_{0} (\frac{v + v _{0}}{v})$
$\frac{f _{a pp} - f _{0}}{f _{0}} = \frac{v _{0}}{v} = \frac{\frac{v}{5}}{v} = \frac{1}{5} = 20%$