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

A man is running with a fork of frequency 340 Hz towards a huge wall with a velocity 2m/s, then the number of beats heard per second is (Velocity of sound in air is 342 m/s)

A train is approaching towards a platform with a speed of 10 ms^(-1) , while blowing a whistle of frequency 340 Hz. What is the frequency of whistle heard by a stationary observer on the platform ? (given, speed of sound =340 ms^(-1) )

A train is approaching towards a platform with a speed of 10 m s^(-1) while blowing a whistle of frequency 340 Hz. What is the frequency of whistle heard by a stationary observer on the platform ? Given speed of sound = 340 ms^(-1) .

One train is approaching an observer at rest and another train is receding him with same velocity 4 ms^(-1) . Both the trains blow whistles of same frequency of 243 Hz. The beat frequency in Hz as heard by the observer is (speed of sound in air= 320ms^(-1) )

A train moving with speed 72 Km/hr blows its whistle of 200 Hz.What frequency is heard by a stationary observer?[velocity of sound in air = 330 m(s)^-1 ]

A train is travelling at 120kmph and blows a whistle of frequency 1000Hz . The frequency of the note heard by a stationary observer if the train is approaching him and moving away from him are (Velocity of sound in air =330=ms^(-1) )