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A man standing on a platform observes th...

A man standing on a platform observes that the frequency of the sound of a whistle emitted by a train drops by 140 Hz. If the velocity of sound in air is 330 m/s and the speed of the train is 70 m/s, the frequency of the whistle is

A

571 Hz

B

800 Hz

C

400 Hz

D

260 Hz

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The correct Answer is:
B
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