Waves Test - 67...

A source of sound is moving with constant velocity of 20 m/s emitting a note of frequency 1000 Hz . The ratio of frequencies observed by a stationary observer while the source is approaching him and after it crosses him will be (Speed of sound v = 340 m/s)

A source and listener are both moving towards each other with speed v/10 , where v is the speed of sound. If the frequency of the note emitted by the source is f, the frequency heard by the listener would be nearly

A table is revolving on its axis at 5 revolutions per second. A sound source of frequency 1000 Hz is fixed on the table at 70 cm from the axis. The minimum frequency heard by a. listener standing at a distance from the table will be (speed of sound = 352 m/s)

A motor car blowing a horn of frequency 124 vib/sec moves with a velocity 72 km/hr towards a tall wall. The frequency of the reflected sound heard by the driver will be (velocity of sound in air is 330 m/s)

A source of sound of frequency n is moving towards a stationary observer with a speed S. If the speed of sound in air is V and the frequency heard by the observer is n₁, the value of n₁/n is

A whistle giving out 450 Hz approaches a stationary observer at a speed of 33 m/s. The frequency heard by the observer in Hz is

An observer is moving away from source of sound of frequency 100 Hz. His speed is 33 m/s. If speed of sound is 330 m/s, then the observed frequency is

An observer standing at station observes frequency 219 Hz where a train approaches and 184 Hz when train goes away from him. If velocity of sound in air is 340 m/s, then velocity of train and actual frequency of whistle will be

At what speed should a source of sound move so that stationary observer finds the apparent frequency equal to half of the original frequency?

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)