# Electromagnetic radiation and Flaw of De-Broglie Equation

by curious bishal
Tags: debroglie, electromagnetic, equation, flaw, radiation
 P: 128 The momentum of a photon is not $mv$, it's $E/c$. This follows from Einstein's $E^2=p^2c^2+m^2c^4$ for a massless particle. (In addition, the relation $p=\gamma mv$ should be used in relativity for the three-momentum of massive particles, where m is the invariant mass, but that's not very relevant in this case. Just so you know.)