Photon momentum question

Question

What is the momentum of a photon having a wavelength of 2.50 um? What is the velocity of an electron having the same momentum? What is the kinetic energy of the electron?

Answer 1

Momentum of photon = h/wavelength (h = Planck's constant (6.63 x 10^-34)).

Momentum for electron is p=mv.  Mass of electron is 9.11 x 10^-31 kg.  Switch formula to v = p/m.

Kinetic energy of electron is (mv^2)/2.