An Observer Is Moving With Velocity v0 towards A Stationary Sound Source Emitting Waves Of Frequency n. If v is The Velocity Of Sound Waves, Then The Wavelength Of The Sound Waves As Detected By The Observer Will Be:

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An observer is moving with velocity v0 towards a stationary sound source emitting waves of frequency n. If v is the velocity of sound waves, then the wavelength of the sound waves as detected by the observer will be:


Correct option is


Since the observer is moving towards the source, the velocity of sound wave relative to the observer becomes v + v0. As a result, the number of waves, each of wavelength λ, crossing the observer per second, i.e., apparent frequency n’ becomes  


The wavelength observed by the observer will be: 





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