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A train, standing in a station yard, blo...

A train, standing in a station yard, blows a whistle of frequency 400Hz in still air. The wind starts blowing in the direction from the yard to the station with a speed of 10m//s. Given that the speed sound in still air is `34om//s,

A

the frequency of sound as heard by an observer standing on the platform is 400 Hz

B

the speed of sound for the observer standing on the platform is 350 m/s

C

the frequency of sound as heard by the observer standing on the platform will increase

D

the frequency of sound as heard by the observer standing on the platform will decrease.

Text Solution

Verified by Experts

The correct Answer is:
A, B
Frequency of sound waves heard by the observer is not affected by the speed of wind, so n = 400 Hz. Speed of sound observed by the standing observer on the platform `= v + 10 = 340 + 10 = 350 ms^(-1)`.
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