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A siren emitting sound of frequency 800 ...

A siren emitting sound of frequency 800 Hz is going away from a static listener with a speed of 30 m/s. Frequency of the sound to be heard by the listener is (Take velocity of sound as 330 m/s)

A

`733.3 Hz `

B

`481.2 Hz`

C

`644.8 Hz`

D

`286.5 Hz`

Text Solution

Verified by Experts

The correct Answer is:
A

We have `(f _(L))/( v + v _(L)) = (f _(S))/( v + v _(S ))`
`therefore (f _(L))/( 330 + 0) = (800 )/( 330 + 30)`
`therefore f _(L) = 800 xx (330)/(360) = 733.3 Hz`
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