## Derivation of De Broglie wavelength

The De Broglie wavelength was derived like this by our physics teacher.
E=hf v=fλ E=mc^2
so
hf=mc^2
hv=λmc^2
Then the WRONG BIT
h=λmv
h=λρ
λ=h/ρ

But that only works for light (when c=v). There must be a correct way of deriving it for electrons etc. We are expected to use this for electrons.

Recognitions: