Doppler's Effect

When a source of sound wave and an observer approach each other in static air medium, then the wavelength of sound wave appears to the observer to

What is Doppler's effect ? Derive an expression for the apparent frequency, when source and observer are both in motion.

What is Doppler's effect? Derive an expression for the apparent frequency. When observer is in motion.

What is Doppler's effect. ? Derive an expression for the apparent frequency when source is in motion.

The ratio of the apparent frequencies of the horn of a car when approaching and receding stationary observer is $1:9$. What is the speed of the car, if the velocity

of sound in air is $300 \mathrm{m}/\mathrm{s}$.

An observer on a railway station platform observed that as the train passed the station at $96 \mathrm{km}/\mathrm{hr}$., the frequency of the whistle appeared to drop by

$400 \mathrm{Hz}$. Find the frequency of the whistle. (speed of sound $=1200 \mathrm{km}/\mathrm{hr}.)$

A man is standing beside a railway line listening to the whistle of a passing train. The whistle which has a frequency of $1000 \mathrm{Hz}$ suffers an apparent change of $100 \mathrm{Hz}$. What is the speed of the train ? (speed of sound $333.3 \mathrm{m}/\mathrm{s})$

A train approaches a stationary observer at a speed of $75\mathrm{kms}/\mathrm{hr}$ sounding a whistle of frequency $1000 \mathrm{Hz}$. What will be the apparent frequency of the whistle to the observer? (speed of sound $=332 \mathrm{m}/\mathrm{s}$ )

Two tuning forks have identical frequencies, but one is stationary while the other is mounted on a rotating record turntable. What does a listener hear?

Two wires, $\mathrm{A}$ and $\mathrm{B}$ are tied up between any two points. The diameter, tension applied and density of $\mathrm{B}$ are twice those of $\mathrm{A}$. Calculate the frequency of $\mathrm{B}$ relative to that of $\mathrm{A}$.

A sound source and a listener are both at rest on earth, but a strong wind is blowing. Is there a Doppler effect?

How can you conclude that the star is coming towards earth?

What happens to the apparent frequency of a note if the source of sound approaches the listener?

Two sound waves of frequencies $135$ and $140 \mathrm{Hz}$ are superposed on each other. What is the number of beats produced per second?