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A car moves towards a hill with speed vc. It blows a horn of frequency f, which is heard by an observer following the car with speed v0. The speed of sound in air is v.

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Important Questions on Sound Wave And Doppler Effect

MEDIUM
JEE Main
IMPORTANT
Chapterwise/Topicwise Daily Practice Problems (DPP) Waves & Thermodynamics JEE Main & Advanced>Chapter 8 - Sound Wave And Doppler Effect>DPP>Q 1
Two passenger trains moving with a speed of 108 km h-1 cross each other. One of them blows a whistle whose frequency is 750 Hz. If sound speed is 330 m s-1, then passengers sitting in the other train, after trains cross each other will hear sound whose frequency will be, 
MEDIUM
JEE Main
IMPORTANT
Chapterwise/Topicwise Daily Practice Problems (DPP) Waves & Thermodynamics JEE Main & Advanced>Chapter 8 - Sound Wave And Doppler Effect>DPP>Q 2
With what velocity an observer should move relative to a stationary source so that he hears a sound of double the frequency of source?
HARD
JEE Main
IMPORTANT
Chapterwise/Topicwise Daily Practice Problems (DPP) Waves & Thermodynamics JEE Main & Advanced>Chapter 8 - Sound Wave And Doppler Effect>DPP>Q 3
A source of sound is moving with a constant velocity of  20 m s-1 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, 
MEDIUM
JEE Main
IMPORTANT
Chapterwise/Topicwise Daily Practice Problems (DPP) Waves & Thermodynamics JEE Main & Advanced>Chapter 8 - Sound Wave And Doppler Effect>DPP>Q 4
A table is revolving on its axis at 5 rev s-1. 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-1), 
HARD
JEE Main
IMPORTANT
Chapterwise/Topicwise Daily Practice Problems (DPP) Waves & Thermodynamics JEE Main & Advanced>Chapter 8 - Sound Wave And Doppler Effect>DPP>Q 5
A source of the sound S of frequency 500 Hz situated between a stationary observer O and a wall W moves towards the wall with a speed of 2 m s-1. If the velocity of sound is 332 m s-1, then the number of beats per second heard by the observer is (approximately), 
HARD
JEE Main
IMPORTANT
Chapterwise/Topicwise Daily Practice Problems (DPP) Waves & Thermodynamics JEE Main & Advanced>Chapter 8 - Sound Wave And Doppler Effect>DPP>Q 6
A motor car blowing a horn of frequency 124 vib s-1 moves with velocity 72 km h-1 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-1), 
MEDIUM
JEE Main
IMPORTANT
Chapterwise/Topicwise Daily Practice Problems (DPP) Waves & Thermodynamics JEE Main & Advanced>Chapter 8 - Sound Wave And Doppler Effect>DPP>Q 7
An observer standing at station observes frequency 219 Hz when a train approaches and 184 Hz when the train goes away from him. If the velocity of sound in air is 340 m s-1, then the velocity of train and actual frequency of whistle will be, 
MEDIUM
JEE Main
IMPORTANT
Chapterwise/Topicwise Daily Practice Problems (DPP) Waves & Thermodynamics JEE Main & Advanced>Chapter 8 - Sound Wave And Doppler Effect>DPP>Q 8
Two sirens situated one kilometre apart are producing the sound of frequency 330 Hz. An observer starts moving from one siren to the other with a speed of 2 m s-1. If the speed of sound be 330 m s-1, what will be the beat frequency heard by the observer?