When light of appropriate frequency is incident on a metal, then electrons are emitted from that metal. This process of emission of electrons is called photoelectric emission and the effect is called photoelectric effect. The electrons emitted due to the influence of light are called photo-electrons and current produced due to the emission of electrons is called photoelectric current.
Energy of incident light = work function + maximum kinetic energy of an electron.
Work-function: Minimum energy required to release an electron from metal surface.