Doppler Effect

Check out more papers on Force Mechanical Engineering Mechanics

Doppler Effect The Doppler effect (or Doppler shift), named after Austrian physicist Christian Doppler who proposed it in 1842, is the change in frequency of a wave for an observer moving relative to the source of the wave. It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from an observer. The received frequency is higher (compared to the emitted frequency) during the approach, it is identical at the instant of passing by, and it is lower during the recession.

Don't use plagiarized sources. Get your custom essay on

“Doppler Effect”

Get custom essay

If the source moving away from the observer is emitting waves through a medium with an actual frequency f0, then an observer stationary relative to the medium detects waves with a frequency f given by where vs is positive if the source is moving away from the observer, and negative if the source is moving towards the observer. A similar analysis for a moving observer and a stationary source yields the observed frequency (the receiver’s velocity being represented asvr): here the similar convention applies: vr is positive if the observer is moving towards the source, and negative if the observer is moving away from the source. These can be generalized into a single equation with both the source and receiver moving. With a relatively slow moving source, vs,r is small in comparison to v and the equation approximates to where . However the limitations mentioned above still apply.

When the more complicated exact equation is derived without using any approximations (just assuming that source, receiver, and wave or signal are moving linearly relatively to each other) several interesting and perhaps surprising results are found. For example, as Lord Rayleigh noted in his classic book on sound, by properly moving it would be possible to hear a symphony being played backwards. This is the so-called “time reversal effect” of the Doppler effect. Other interesting conclusions are that the Doppler effect is ime-dependent in general (thus we need to know not only the source and receivers’ velocities, but also their positions at a given time), and in some circumstances it is possible to receive two signals or waves from a source, or no signal at all. In addition there are more possibilities than just the receiver approaching the signal and the receiver receding from the signal. All these additional complications are derived for the classical, i. e. , non-relativistic, Doppler effect, but hold for the relativistic Doppler effect as well as.

Did you like this example?

Cite this page

Doppler Effect. (2017, Sep 13). Retrieved December 6, 2022 , from

Save time with Studydriver!

Get in touch with our top writers for a non-plagiarized essays written to satisfy your needs

Get custom essay

Stuck on ideas? Struggling with a concept?

A professional writer will make a clear, mistake-free paper for you!

Get help with your assigment
Leave your email and we will send a sample to you.
Stop wasting your time searching for samples!
You can find a skilled professional who can write any paper for you.
Get unique paper

I'm Chatbot Amy :)

I can help you save hours on your homework. Let's start by finding a writer.

Find Writer