A train moves towards a stationary observer with a speed of 40 m/s. The observer
Channel: Doubtnut
Date: 24/05/2020

A train moves towards a stationary observer with a speed of 40 m/s. The observer records the frequency of the train's whistle as `f_(1)`. But when the train's speed is reduced to 20 m/s, the frequency of the whistle recored by him is `f_(2)`. What is the ratio `(f_(1))/(f_(2))`, if the speed of sound in air is 340 m/s ?