When light of suitable frequency incident on the metal surface, electrons are ejected from the surface. This effect of light is known as photoelectric effect.
The electrons ejected from the metal surface are known as photoelectron and the current associated due to these electrons is known as photocurrent. Generally, for photo electric effect, metal like alkali (Na, K, Ca) are used. From these metals, electrons are emitted even from the light of visible wavelength. Metals like Zn, Cd shows photoelectric effect from the light whose wavelength lies in the ultra violet rays.