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A source of sound S is travelling at (10...


A source of sound S is travelling at `(100)/(3)(m)/(s)` along a road, towards a point A. When the source is 3 m away from A, a person standint at a point O on a road perpendicular to AS hears a sound of requency `v'`. The distance of O from A at that time is 4 m. If the original frequency is 640 Hz, then the value of `v'` is (velocity of sound is `340(m)/(s)`)

A

620 Hz

B

680 Hz

C

720 Hz

D

840 Hz

Text Solution

Verified by Experts

The correct Answer is:
B

Effective value of velocity of source is
`v_S=(100)/(3)costheta`
`=(100)/(3)xx(3)/(5)=20(m)/(s)`
`v'=(v)/(v-v_S)v`
`v'=(340)/(340-20)xx640Hz=680Hz`
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CENGAGE PHYSICS ENGLISH-SOUND WAVES AND DOPPLER EFFECT-Single Correct
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