What is the mass of a photon?

Question

Or does it only have inferred mass, form its energy. If so, what is its energy?

Vote will have to do. I have no clue what the best answer is.

Answer 1

photons are just elementary particles of light, so they do not have any mass and I think the energy is proportional to its frequency.

edit - Photons themselves are massless (if they weren't they couldn't travel at the speed of light), but they do add mass to a system they are a part of and I'm guessing those are the values shown below.

Answer 2

A photon always has the speed C in vacuum.

Thus it has always a kinetic energy given by the formula hn, where n is the frequency of the photon.

When it tdravels inside a material medium it speed is reduced.

Its kinetic energy is reduced; but its total energy remains the same as hn.

It is the reason when it comes out of the material and enters vacuum it regains it speed as C.

About the mass of photon, by relativistic theory, now we know mass is a property which tells us the energy of a body.

The 'mass' in classical physics has lost its absolute nature.

Now it is the measure of the energy.

Instead of saying 9x10^16 joule of enegy one can as well say that 1 kg mass.

Mass is relative and varies with speed.

Relative to an observer if a particle is at rest, let its mass be m0.

If it moves with a speed v,
then its kinetic energy is not 0.5 mo V^2.

It is m*C*C. The m is not m0 but has increased from m0 to m.

The kinetic energy is (m- m0) C C. and m C C is the total energy . m0 CC is the energy ( internal energy) whent it is at rest.

In the case of photon its velocity is independent of the frame of reference. It is always has a speed of C in vacuum.

Thus it has no rest mass. But lit has kinetice energy and hence has a mass given by the equation m C C = hn.

Or mass of photon = m = hn/ C^2.

But this is not the rest mass of photon which is always zero in vacuum.

Answer 3

I dont be attentive to with reference to the a lot yet a photon is amazingly a 'packet' of light. whilst an electron is worked up from its floor state, it quickly drops backpedal to the floor state dropping the surplus capability interior the technique. the surplus capability is given off as a photon.

Answer 4

This question comes up in the context of wondering whether photons are really "massless," since, after all, they have nonzero energy and energy is equivalent to mass according to Einstein's equation E=mc2
For more information click on the following link.

http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.html

Answer 5

photon doesn't have any mass. it is known light is made up of photon. Photon has momentum and energy. it's is also a fact photon can exert force on an object, but it's plausible for momentum to exist without mass.

Answer 6

None! photons occupy no space and have no mass. There is energy but unless it is combined in a form that materializes perceived reality it has no Newtonian Physics.

Answer 7

Physicists tell us that the photon would have a tiny rest mass, but since a photon is never at rest it actually has no mass.

Answer 8

Check out this site, which claims light's mass cannot be absolutely zero (it would mess up relativity if it were), although 10^-51 grams is pretty close!

http://www.aip.org/pnu/2003/split/625-2.html

Answer 9

DEPENDING THE STUDY THERE ARE TWO VERSIONS OF THE STORY.
THE FIRST CLAIMS THAT UNDER CERTAIN STUDIES AND OBSERVATIONS A PHOTON MAY HAVE A CERTAIN MASS.
THE SECOND CLAIMS THE CONTRARY, CLAIMING IT DOES NOT HAS ANY MASS.

I GUESS WE ARE MISSING A THIRD UNIFYING THEORY OF THESE TWO ABOVE