Photons

Photons are electrically neutral and always move with the speed of light.

Photon energy:  E = hf
Photon momentum:  p = hf/c = h/λ
h = 6.626*10^-34 Js
1 eV = 1.6*10^-19J

Photoelectric effect:  Energy of ejected electron = hf - φ,  (φ = work function of the metal)