Questions in waves

SelectQuestion
A source of sound of frequency 90 vibrations/ sec is approaching a stationary observer with a speed equal to 1/10 the speed of sound. What will be the frequency heard by the observer
A whistle of frequency 500 Hz tied to the end of a string of length 1.2 m revolves at 400 rev/min. A listener standing some distance away in the plane of rotation of whistle hears frequencies in the range (speed of sound = 340 m/s)
A train moves towards a stationary observer with speed 34 m/s. The train sounds a whistle and its frequency registered by the observer is ${{f}_{1}}$. If the train’s speed is reduced to 17 m/s, the frequency registered is ${{f}_{2}}$. If the speed of sound is 340 m/s then the ratio ${{f}_{1}}/{{f}_{2}}$ is
If source and observer both are relatively at rest and if speed of sound is increased then frequency heard by observer will
A source and an observer move away from each other with a velocity of 10 m/s with respect to ground. If the observer finds the frequency of sound coming from the source as 1950 Hz, then actual frequency of the source is (velocity of sound in air = 340 m/s)
A source is moving towards an observer with a speed of 20 m/s and having frequency of 240 Hz. The observer is now moving towards the source with a speed of 20 m/s. Apparent frequency heard by observer, if velocity of sound is 340 m/s, is
A siren placed at a railway platform is emitting sound of frequency 5 kHz. A passenger sitting in a moving train A records a frequency of 5.5 kHz while the train approaches the siren. During his return journey in a different train B he records a frequency of 6.0 kHz while approaching the same siren. The ratio of the velocity of train B to that of train A is
A whistle revolves in a circle with an angular speed of 20 rad/sec using a string of length 50 cm. If the frequency of sound from the whistle is 385 Hz, then what is the minimum frequency heard by an observer, which is far away from the centre in the same plane ? (v = 340 m/s)
A Siren emitting sound of frequency 800 Hz is going away from a static listener with a speed of 30 m/s, frequency of the sound to be heard by the listener is (take velocity of sound as 330 m/s)
A car sounding a horn of frequency 1000 Hz passes an observer. The ratio of frequencies of the horn noted by the observer before and after passing of the car is $11 : 9$. If the speed of sound is $v$, the speed of the car is

View Selected Questions (0)

Back to Categories

Back to Home