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Do photons have mass?
If photons have zero mass, then their energy should be zero by E = m c^2 or E^2 = m^2 c^4 + p^2 c^2 because p = m v. If they have mass, they can't travel at the speed of light.
4 Answers
- 1 decade agoFavorite Answer
There is proof either way. Photons do have momentum, and they can knock electrons out of their orbitals, but they couldn't travel at the speed of light if they were massive. Photons do have energy, and according to e=mc^2 if they have energy they must have mass >0. I personally think it's both or neither, as it's quantum physics and such things could be possible in the quantum world.
- ukmudgalLv 61 decade ago
Rest mass of a photon is zero,energy of a photon E=hf where h is Planck's constant and f is frequency of photon
Momentum of photon =h/ wavelength
Speed of photon in vacuum is c=3*10^8 m/s
- GeneLv 71 decade ago
Look at this article. It's actually not bad and doesn't need an understanding of some hairy math
- 1 decade ago
But if they didn't have mass, their speed would be infinite. Their mass is finitely small.
