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.
2007-04-18 09:41:29 · 4 answers · asked by Liquid Astatine 2 in Science & Mathematics ➔ Physics
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.
2007-04-19 08:35:55 · answer #1 · answered by Superconductive Magnet 4 · 0⤊ 0⤋
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
2007-04-18 10:17:28 · answer #2 · answered by ukmudgal 6 · 0⤊ 0⤋
Look at this article. It's actually not bad and doesn't need an understanding of some hairy math
http://www.usatoday.com/weather/resources/basics/wonderquest/photonmass.htm
2007-04-18 09:49:05 · answer #3 · answered by Gene 7 · 0⤊ 0⤋
But if they didn't have mass, their speed would be infinite. Their mass is finitely small.
2007-04-18 09:45:46 · answer #4 · answered by LaserPhaser 2 · 0⤊ 1⤋