A train approaches stationary observer, the velocity of train being `1/20` of the velocity of sound. A sharp blast is blown with the whistle of the engine at equal intervals of 1s. The interval between the successive blasts as heard by the observer

An observer is approaching a stationary source with a velocity 1/4 th of the velocity of sound. Then the ratio of the apparent frequency to actual frequency of source is

A train moving at 40 m/s, passes by a stationary observer, emitting a whistle of frequency 300 Hz. If the velocity of sound wave is 340 m/s, then the change in the apparent frequency of the sound, just before and after the train passes by the observer will be nearly

When an engine passes near to a stationary observer then its apparent frequencies occurs in the ratio 5/3. if the velocity of sound is 340 m/s then speed of engine is

A source of sound crosses a stationary observer which is moving with uniform velocity v. If the velocity of sound in air is V, then the ratio of the apparent frequencies heard by the observer before and after the source crosses him would be -

A sound source emitting sound of frequency 450 Hz is approaching a stationary observer with velocity 30 ms^(-1) and another identical source is going away from the observer with the same velocity. If the velocity of sound is 330 ms^(-1) , then the difference of frequencies heard by observer is

A source of frequency 1 kHz is moving towards a stationary observer with velocity of 0.9 times that of sound. What is the frequency heard by the observer ?

One train is approaching an observer at rest and another train is receding from him with the same velocity 4 m//s . Both trains blow whistles of same frequency of 243 H_(Z) . The beat frequency in H_(Z) as heard by observer is (speed of sound in air = 320 m//s )