# Do photons have mass?

1. Jun 12, 2015

### Suraj Nehra

I read the FAQ about photons not having mass: Do photons have mass?

But De-Broglie's equation says that wavelength=Plank constant / mass x velocity
i.e.
λ=h/mv

inserting values in the above relation we find the mass of a photon having certain wavelength

Last edited by a moderator: Jun 14, 2015
2. Jun 12, 2015

### ChrisVer

You wrote the debroglie equation for a massive particle (where you can write its momentum as p=mv which is not correct for the photon). You should use instead $\lambda= \frac{h}{p}$.