A man standing on a platform observes that the frequency of the sound of a whistle
Channel: Doubtnut
Date: 2020-03-29

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