Quick 'n' easy question about doppler effect

AI Thread Summary
The discussion centers on the derivation of the Doppler effect formula, specifically how it relates to classical speed addition and its differences for light and electromagnetic waves. It highlights that light maintains a constant speed for all observers, resulting in frequency and wavelength shifts rather than classical particle behavior. Participants express confusion over the representation of the relativistic Doppler effect on a referenced page, questioning its derivation and form. Clarification is provided that the equation in question is a reformulation of the relativistic Doppler formula, useful for low-speed approximations. Understanding these nuances is essential for grasping the complexities of the Doppler effect in different contexts.
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Doppler effect revisited

Am I right when I say that the doppler effect formula "f=f0((v+vo)/(v+vs))" is derivated from the classical theorem of speed addition and this is why the doppler effect for light and EM waves is different?
 
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Because light does not behave as a classical particle, it has a constant speed for all observers. It is frequency and wavelength which undergo a Doppler shift in light.
 
I'm a little confused here...

I don't get how on this page: hyperphysics they get the first equation... I don't see the relativistic doppler effect written that way anywhere and I don't understand how they get ot that equation and how to expand it with maple...Anybody can help?
 
That equation is just the relativistic Doppler formula rewritten in a form convenient for deriving the low speed approximation. They took something that usually appears in a form like:
\sqrt{\frac{1 + x}{1 - x}}
And rewrote it like:
\frac{\sqrt{1 - x^2}}{1 - x}
These expressions are equivalent.
 
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