﻿ A sound wave of wavelength λ travels towards the right horizontally with a velocity v. It strikes and reflects from a vertical plane surface, travelling at a speed v towards the left. The number of positive crests striking in a time interval of three seconds on the wall is: : Kaysons Education

# A Sound Wave Of Wavelength λ Travels Towards The Right Horizontally With A Velocity v. It Strikes And Reflects From A Vertical Plane Surface, Travelling At A Speed v towards The Left. The Number Of Positive Crests Striking In A Time Interval Of Three Seconds On The Wall Is:

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The relative velocity of sound waves with respect to the walls is V + v. Hence, the apparent frequency of the waves striking the surface of the wall is (V + v)/λ. The number of positive crests striking per second is the same as frequency. In three seconds, the number is [3(V + v)]/ λ.

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