Einstein proposed an explanation of the photoelectric effect using a concept first put forward by Max Planck that light waves consist of tiny bundles or packets of energy known as photons or quanta. When a photon falls on the surface of a metal, the entire photon’s energy is transferred to the electron. A part of this energy is used to remove the electron from the metal atom’s grasp and the rest is given to the ejected electron as kinetic energy. Electrons emitted from underneath the metal surface lose some of the kinetic energy in collisions. But the surface electrons carry all the kinetic energy imparted by the photon and have the maximum kinetic energy.
We can write this mathematically as E = W + Kmax
maximum wavelength of visible light = 7700 A0
Energy
Work function depends only on nature of metal.
So that kinetic energy of an electron increase when frequency of radiation increases.