# Emission of a photon

energy and mass are same by E=mc^2

No.it does not have.One basic reason is gauge invariance.

two photons can create particle antiparticle pair.They have energy which is converted to mass.

You may have written you need energy to create mass or vice versa.

Every photon has energy,momentum,spin.Energy is simply E=h-ω
is a photon a force . like gravity, magnetic fields etc. are forces create by mass ?????

is a photon a force . like gravity, magnetic fields etc. are forces create by mass ?????
Electromagnetic (mediated by photons), strong (mediated by gluons) and weak (mediated by W and Z bosons) interactions are mediated by virtual particles. Graviton is also a hypothetical boson that mediates gravity.

is a photon a force . like gravity, magnetic fields etc. are forces create by mass ?????
electromagnetic interaction is mediated by photons.

mfb
Mentor
isn't mass the the only source of energy
No, it is just one type of energy.

energy and mass are same by E=mc^2
Only if you use the concept of relativistic mass, which is done in ancient textbooks and bad TV documentations only.

Only if you use the concept of relativistic mass, which is done in ancient textbooks and bad TV documentations only.
mass of electron in natural units is 0.511 Mev.

mfb
Mentor
I don't see how your post is related to the others in this thread.
c=1 is a conventional choice, but this does not mean that my height is some nanometers.

that is just a conventional way.To get back to original requires some work.And what you don't see.

K^2
You are missing the point. E=mc² is wrong. The correct formula is E² = p²c² + (mc²)²

You are missing the point. E=mc² is wrong. The correct formula is E² = p²c² + (mc²)²
if you don't use the definition of relativistic mass then,right.Otherwise both are same.Energy is time component of four momentum and mass is invariant,so they are really different. if one avoids the notion of relativistic mass which is already abandoned then of course it is wrong.But that is just not what I say.It is a matter of definition.

K^2