It appears that you're using the equation for the energy of a photon in terms of its wavelength. In that case the correct relationship is

E = hf

If you want the relativistic mass of the photon the start with the relationship between the photons energy and its momentum which is E = pc. The relation between its momentum and speed is p = mc. Solve for m and you get E = mc^{2}.

I was in a hurry when I wrote that so let me finish it by working out the details.

If E is the energy of a photon and f is the frequency of the same photon then the energy is related to its frequency by E = hf. If p is the momentum of the photon and m is the photons relativistic mass then p = mc. The relationship between a photons energy and its momentum is E = pc. If we substitute p = mc into E = mc we get E = (mc)c = mc

^{2}.

If the object is

*not* a photon then the same relation holds true. The derivation is too long to put into this post. However I wrote up a derivation and placed it on my website for just this kind of reason. See:

http://www.newenglandphysics.org/physics_world/sr/mass_energy_equiv.htmYes I know you think E=hf but in reality PE=hf the ''energy'' is not ''created'' until the interaction with ''matter''. It remains potential ''energy'' until interaction.

Leave it to you to make such erroneous claims. Its for this

*exact* reason that I stopped trying to help you. Not only do you not know what you're talking about but you've never been willing to learn from others who know these subjects so much better than you do. In this case it's been well-established that E = hf is a valid relationship and E is the

*kinetic energy* of the photon and

*not* its potential energy. E = hf is defined as the total energy of a photon in an inertial frame of reference and as such the gravitational potential energy of the photon is zero leaving only kinetic energy. It's impossible for a photon to have any electric potential energy U because U is proportional to the charge of the particle in question. Since photons have zero charge that leaves U = 0 which leaves E = K = hf. Anybody who knows quantum mechanic will tell you that.

I've deleted the rest of your garbage and adding you to my ignore list with the other members here who don't have the ability to either learn physics or play nice.

How do all of you folks tolerate this person?