Hert's observation-Explain in short.

Explanation

Photoelectric effect was first observed by scientist Hertz in 1887.
Hertz made experimental investigation of production of electromagnetic waves by means of spark discharge.
Hertz observed that high voltage spark across detector loop were enhanced when the emitter plate was illuminated by ultraviolet light from an arc lamp when light is incident on meral surface.Some electrons near metal surface,some electrons near metal surface,some electrons near the surface absorb enough energy,from incident radiation to overcome attraction of positive ions is the metal surface.
After gaining sufficient energy from incident light,the electrons escape from the surface of the metal into surrounding space.