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`)

A train is moving with speed 72 km/h towards a hill blows a whistle of frequency 1240Hz. the frequency of echo heard by driver is(speed of sound=330m/s)

A train in approaching a station with a uniform velocity of 72kmph and the frequency of the whistle of that train is 480Hz . The apparent increase in the frequency of that whistle heard by a stationary observer on the platform is (Velocity of sound in air is 340m//s )

A whistle giving out 450 H_(Z) approaches a stationary observer at a speed of 33 m//s . The frequency heard the observer (in H_(Z) ) is (speed of sound = 330 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 man is watching two trains, one leaving and the other coming in with equal speed of 4 m/s . If they sound their whistles, each of frequency 240 Hz, the number of beats heard by the man (velocity of sound in air is 320(m)/(s) ) will be equal to

a bus is moving towards and stationary observer with speed 20 m/s blows a horn of frequency 200 Hz. the frequency of sound heard by the observer is approximately ( take speed of sound 320 m/s)

A stationary observer receives sonic oscillations from two tuning forks one of which approaches and the other recedes with the same velocity. As this takes place, the observer hears the beats of frequency f = 2.0 H_(Z) . Find the velocity of each tuning fork if their oscillation frequency is f_(o) = 680 H_(Z) and the velocity of sound in air is upsilon = 340 m//s .

Two trains A and B are moving in the same direction with velocities 30 m/s and 10 m/s respectively, B is behind from A, blows a horn of frequency 450 Hz. Then the apparent frequency heard by B is (The velocity of sound is 330 m/s) :-