List of top Physics Questions on doppler effect

A passenger is sitting in a fast moving train. The engine of the train blows a whistle of frequency N. If the apparent frequency of sound heard by the passengers is \( N' \), then:
A train is moving with a speed of \(10 m/s\) towards a platform and blows a horn with frequency \(400 Hz\). Find the frequency heard by a passenger standing on the platform. Take speed of sound = \(310 m/s\).

A source of sound is moving away from a stationary observer with constant velocity 40 m/s. Find frequency heard by observer, if original frequency of source is 400 Hz and speed of sound in air is 360 m/s

A car P travelling at 20 \(ms^{–1}\) sounds its horn at a frequency of 400 Hz. Another car Q is travelling being the first car in the same direction with a velocity 40 \(ms^{–1}\) . The frequency heard by the passenger of the car Q is approximately [Take, velocity of sound = 360 \(ms^{–1}\) ]

A source of sound S emitting waves of frequency 100Hz and an observer O are located at some distance from each other. The source is moving with a speed of 19.4m s⁻1 at an angle of 60^∘ with the source–observer line as shown in the figure. The observer is at rest. Find the apparent frequency observed by the observer. (Velocity of sound in air =330m s⁻1). 

Two tuning forks with natural frequencies 340 Hz each move relative to a stationary observer. One fork moves away from the observer, while the other moves towards the observer at the same speed. The observer hears beats of frequency 3 Hz. Find the speed of the tuning forks.

A source of sound S emitting waves of frequency 100Hz and an observer O are located at some distance from each other. The source is moving with a speed of 19.4m s⁻1 at an angle of \(60^\circ\) with the source–observer line as shown. The observer is at rest. The apparent frequency observed is (velocity of sound in air =330m s⁻1):  

Two tuning forks with natural frequencies 340 Hz each move relative to a stationary observer. One fork moves away from the observer while the other moves towards the observer with the same speed. The observer hears beats of frequency 3 Hz. Find the speed of the tuning forks.

A sound source, emitting sound of constant frequency, moves with a constant speed and crosses a stationary observer. The frequency \(n\) of sound heard by the observer is plotted against time \(t\). Which of the following graphs represents the correct variation? 

A sound source is moving towards a stationary listener with \( \frac{1}{10} \)th of the speed of sound. The ratio of apparent to read frequency is:
A source has wavelength 60 cm when it is stationary. If the speed of sound in air is 320m s⁻¹ and the source moves with speed 20m s⁻¹, the wavelength in the forward direction will be