A train approaching a railway platform with a speed of 20 ms − 1 starts blowing the whistle. Speed of sound in air is 340 ms − 1 . If the frequency of the emitted sound from the whistle is 640 Hz , th

Question

A train approaching a railway platform with a speed of $20 ms^{- 1}$ starts blowing the whistle. Speed of sound in air is $340 ms^{- 1}$ . If the frequency of the emitted sound from the whistle is $640 Hz$ , the frequency of sound to a person standing on the platform will appear to be

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Answer:

C

Solution:

Given $v = 340 ms^{- 1}, u_{5} = 20 ms^{- 1}$ and $v_{0} = 640 Hz$ From Doppler's law, $v = (\frac{340}{340 - 20}) 640 v = 680 Hz$

TestHub · Accepted Answer

Given v = 340 ms − 1 , u 5 ​ = 20 ms − 1 and v 0 ​ = 640 Hz From Doppler's law, v = ( 340 − 20 340 ​ ) 640 v = 680 Hz ​

Physics - Sound Wave Question with Solution | TestHub

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