Mass of a Photon

  • Thread starter Phys_Boi
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  • #1
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If the energy of a photon: Ephoton = hν, where h = Planck's constant,
and E = mc2, then does hv = mc2

And if so, if c=vλ: Ephoton = hc/λ = mc2

Thus mass: m = h/λc ?
 

Answers and Replies

  • #2
Khashishi
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##E=mc^2## only applies to massive particles at rest, not photons. You need to use the full equation which is
##E^2 = m^2c^4 + p^2 c^2##
 
  • #3
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##E=mc^2## only applies to massive particles at rest, not photons. You need to use the full equation which is
##E^2 = m^2c^4 + p^2 c^2##
So what is the momentum of photons since gravitation is applied?
 
  • #4
Khashishi
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Set m=0 and you get ##E = pc##. You can solve for the momentum of the photon.
 
  • #5
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Set m=0 and you get ##E = pc##. You can solve for the momentum of the photon.
Ah. Thank you
 
  • #6
ZapperZ
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Please note that this has been covered and answered in one of our FAQ.

Zz.
 
Last edited:

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