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A source of sound of frequency 640 Hz is...

A source of sound of frequency 640 Hz is moving at a velocity of `100/3m//s` along a road, and is at an instant 30m away from pint A on the road (as shown in figure. A person standing at O, 40m away from the road hears sound of apperent frequency v'. The value of v' is (velocity of sound =`340m//s`)

A

620 Hz

B

680 Hz

C

720 Hz

D

840 Hz

Text Solution

Verified by Experts

The correct Answer is:
B
The velocity of sound is given by,`V=V_0[V/(V-V_(s)costheta)]`
`:. v=640[340/(340-100/3xx3/5)]=680 "Hz"`
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