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Photon kinetic energy 
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#1
Apr2908, 02:50 PM

P: 364

How is a photon's energy determine in relation to it's wavelength and frequency?
For example, 20hz vs. 400ghz electromagnetic waves. 


#2
Apr2908, 03:19 PM

P: 2,954

Pete 


#3
Apr2908, 08:58 PM

P: 364

can E=1/2mv^2 be applied to photons ever?
or E=mc^2 


#4
Apr2908, 11:10 PM

P: 410

Photon kinetic energy
The proper relativistic equation is
:[tex]E^2 = p^2c^2 + m^2 c^4[/tex], which works just fine for photons when [tex]m = 0[/tex]. For ordinary particles, one can Taylor expand [tex]E = \sqrt{p^2c^2 + m^2 c^4}[/tex] to get a nonrelativistic equation most people use... but for photons, you can't do this, and [tex]E = pc[/tex] simply. According to de Broglie, [tex]p = h \nu[/tex], of course. 


#5
Apr3008, 07:16 PM

P: 2,954

Pete 


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