# The Naked Scientists Forum

### Author Topic: How does the Doppler effect work with light?  (Read 5460 times)

#### Tracy Fincham

• Guest
##### How does the Doppler effect work with light?
« on: 02/09/2008 18:26:11 »
Tracy Fincham  asked the Naked Scientists:

Hi,

I listen to your show whenever possible on 567 Cape Talk.

I realise that you have answered many questions about the speed of light. One thing that I am still not clear on: I was taught that the speed of light is absolute irrespective of the frame of reference which I find difficult to understand. Is this true? If so, how does the Doppler effect work with light?

Thank-you,

Arthur Fincham

What do you think?

#### RD

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##### How does the Doppler effect work with light?
« Reply #1 on: 02/09/2008 18:54:26 »
The Doppler effect changes the frequency and the wavelength of a sound wave, but not the speed of the sound.

#### chris

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• The Naked Scientist
##### How does the Doppler effect work with light?
« Reply #2 on: 11/09/2008 09:59:18 »
Exactly, so the same applies to light. In fact if the speed were to change then the Doppler effect wouldn't work - it relies on the constant relationship c=f.lambda (speed (c) = f (frequency) times lambda (wavelength).

Chris

#### The Naked Scientists Forum

##### How does the Doppler effect work with light?
« Reply #2 on: 11/09/2008 09:59:18 »