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Two cars A and B are moving towards each...

Two cars A and B are moving towards each other with samne speed 25 m/s. wind is blowing with speed 5 m/s in the direction of motion of car A. The car A blows horn of frequency 300 Hz and the sound is reflected from car B. the wavelength of te reflected sound received by the driver of car A is (velocity of sound in air =330m/s)

A

`(25)/(36)m`

B

`(31)/(36)m`

C

`(35)/(36)m`

D

`(37)/(36)m`

Text Solution

Verified by Experts

The correct Answer is:
B
Frequency received by car B is `f_(1)=((v+w+u)/(v+w-u))f`
Now te car B will be treated as a source of frequency `f_(1)`
`therefore` wavelength of reflected sound received by the driver of car A is
`lamda'=((v-w-u))/(f_(1))=((v-w-u)(v+w-))/((v+w+u)f)`
`((330-5-25)(330+5-25))/((330+5+25)300)=(31)/(36)m`
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