A source of sound is moving with a velocity of `50ms^(-1)` towards a stationary observer . The Observer measure the frequency of sound as 500Hz. The appartment frequency of sound as heard by the observer when source is moving away from hom with the same speed is (Speed of sound at room temperature `350ms^(-1)`

Options

A. 400Hz
B. 666Hz
C. 375Hz
D. 177.5Hz

Answer

c

Explanation

`V_(s)=50ms^(-1),V_(0)=0,upsilon=500Hz, V=350ms^(-1)`
When source is moving to words stationary observer
`upsilon.=frac(V)((V-V_(s)))" ". ..(i)`
when source is moving away from stationary observer, `upsilon..=(frac(V)(V+V_(s)))upsilon`
or, `upsilon..=(frac(V-V_(s))(V+V_(s)))upsilon.` using eqn.(i)
`=(frac(350-50)(350+50))xx500=375Hz`