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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

zero

B

0.005

C

0.05

D

0.2

Text Solution

Verified by Experts

The correct Answer is:
D
Given that `v_("observer")=(v_("sound"))/(5)`
Applying Doppler's effect, we get
`f'=f[(v+v_(0))/(v)],f'=f[(6v//5)/(v)]=(6)/(5),(f')/(f)=(6)/(5)`
`(f'-f)/(f)=(6)/(5)-1=(1)/(5)=20%`.
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