Archived Planck's law and doppler effect

AI Thread Summary
The discussion focuses on proving Planck's Law, E=h*u, using the Doppler effect equation. The attempt involves applying Lorentz transformations to relate the energy and frequency of light observed by a moving observer. The calculations show a relationship between the original and observed frequencies, but there is uncertainty about deriving photon energy solely from the Doppler effect. It is suggested that additional information is necessary to complete the proof. The conversation emphasizes the complexity of linking these two fundamental concepts in physics.
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Hello, We proved something during the course but I totally forgot how to do it..

Homework Statement


Prove that Planck's Law E=h*u is deduced from the equation of Doppler effect u'=u*√((1-β)/(1+β))

Homework Equations


Lorentz transformation

The Attempt at a Solution


If we take a beam of light of frequency u and an observer with speed Bc
I don't know if it's correct..
u'=u√((1-β)/(1+β))
E'=y(E-B*Px*c)
And px*c=E so
E'=y(E-BE)
=yE(1-B)
=E√((1-β))/(√((1-β)/(1+β)))
=E√((1-β))/√(1+β)
E'=E*u'/u
E'*u=E*u'
E'/u'=E/u
E/u=cste=h ?
 
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I don't think that the energy of a photon can be derived solely from a consideration of the Doppler effect (relativistic or not). More information is needed.
 
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