A boy is walking away from a wall towards an observer at a speed of $$1$$ $$metre/$$$$sec$$ and blows a whistle whose frequency is $$680$$ Hz. The number of beats heard by the observer per second is $$(Velocity$$ of sound in air $$=$$ $$340$$ $$metres/$$$$sec$$

Question

Infinity Learn · Accepted Answer

Observer hears two frequencies (i)  $$n1$$ which is coming from the source $$directly(ii)$$  $$n2$$ which is coming from the reflection image of sourceso, $$n1=680340340$$−$$1$$ and $$n2=680340340+1$$⇒$$n1$$−$$n2=4$$ beats

A boy is walking away from a wall towards an observer at a speed of 1 metre/sec and blows a whistle whose frequency is 680 Hz. The number of beats heard by the observer per second is (Velocity of sound in air = 340 metres/sec

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