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Two cars A and B approach a statinary ob...

Two cars A and B approach a statinary observer from opposite sides as shown in figure. Observer hears no beats. If the frequency of the horn of the car B is 504 Hz, the frequency of horn of car A will be

A

529.2 Hz

B

295.2Hz

C

440.5Hz

D

259.2Hz

Text Solution

Verified by Experts

The correct Answer is:
A
From Doppler's effect, the apparent change in frequency of a wave that is perceived by stationary observer is
`n'=n_(0)((v)/(v-v_(S)))`
where, v is speed of sound. Since, observer is not hearing any beats, observer is not hearing any beats, the apparent frequency of the two cars should be equal.
`thereforen'=n"`
`504((v)/(v-30))=n((v)/(v-15))`
`thereforen=((330-15)xx504)/((330-30))`
`=(315xx504)/(300)=529.2Hz`
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