Question

How much energy must a photon have if it is to have the momentum of a 10-mev proton?

Answer 1

For massless particles like photons, the energy is related to the momentum by E=p/cE=p/c, where cc is the speed of light. We can do the arithmetic, but this would result in a salad of units, so physicists simply define a new unit of momentum, “electron-Volts per c”, or eV/ceV/c. So the momentum is just 10eV/c10eV/c.

Answer 2

Explanation:

E=p*c

E=10*10^6*10^-19*1.6

E=4.8*10^-4