This is a basic photoelectric type question.
What wavelength of light is necessary to produce photo-electrons of speed 2 * 10^6 m/s with a magnesium target?
KE = pf - phi
phi = 3.7 eV
h = 6.63 * 10 ^-34
The Attempt at a Solution
I don't know how to find the energy of an electron from the velocity. Once I have that I think I can figure it out