Two photons move in opposite directions. One has energy 4 eV, and the other 9 eV?

Question

What is rest mass Mo of the PAIR of photons?

Answer 1

The total momentum is

p = p1-p2 = (E1-E2)/c

The total energy is

E = E1+E2.

If we think the system of two photons as a single particle with this energy and this momentum, it must satisfy the energy-momentum relationship

E^2 = p^2c^2 + m0 c^4

Then

(E1+E2)^2 = (E1-E2)^2 + m0 c^4

or

m0 = 4 E1 E2 / c^4

Answer 2

Photons, per se, have no rest mass.

But if you want to determine how much rest mass they could be converted into, simply divided the total eV by the speed of light squared (c^2). If they both struck the earth, the photons would increase earth's rest mass by 13 eV/c^2

Answer 3

suitable it is the formula: learn help – a thank you to compute the photon means in eV, given wavelength in nm. remember that the photon means is given via skill of E = hf = hc/(wavelength). Calculating the aptitude in joules is simple adequate, yet in many circumstances it is sensible to have the skill at the instant to compute the aptitude in eV at the instant via skill of understanding the wavelength in nm. The conversion from joules to eV is achieved via skill of dividing via skill of a million.6 x 10-19 J/eV. The transformation from meters to nanometers is comprehensive via skill of expressing wavelength in nm and multiplying via skill of the element 10 -9.

Answer 4

I'm going to get out of my depth very fast with this one..but isn't the rest mass of a photon zero?

since I'm out of my depth here's a link instead http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/photonMass.html