A siren emitting sound of frequency (800 ~Hz ) is going away from a static listener with a speed of (30 ~m / s ). The frequency of sound heard by listener is (velocity of sound (=300 ~m / s ) )

Step-by-step solution

Here, (v=800 ~Hz , v_s=30 ~m / s , v=300 ~m / s ). As the source is going away from the stationary observer, therefore, (v^ = v v v+v_s = 300 800 300+30 = 300 800 330 =727.3 ~Hz . )