A siren emitting a sound of frequency 800 Hz moves away from an observer towards a cliff at a speed of 15 ms^(-1)Then, the frequency of sound that the observer hears in the echo reflected from the cliff is ....... (Take velocity of sound in air = 330 ms^(-1))

A siren emitting a sound of frequency 800 Hz moves away from an observ

1.	A siren emitting a sound of frequency 800 Hz moves away from an observer towards a cliff at a speed of 15 ms^(-1)Then, the frequency of sound that the observer hears in the echo reflected from the cliff is ....... (Take velocity of sound in air = 330 ms^(-1))
Answer» 800 Hz 838 Hz 885 Hz 765 Hz SOLUTION : We have `(f _(L))/( v + v _(L)) = (f _(S))/( v + v ._(S))` `therefore (f _(L))/( 330 + 0) = (800)/( 330 - 15)` `therefore f _(L) = 800 xx (330)/(315) = 838.1Hz`