Question

what is photo electric effect

Answer 1

The photoelectric effect is the emission of electrons from the surface of a metal by incident light. It is due to the particle nature of light. Photons (particles of light) with an energy above a specific threshold (the threshold is material dependent, and is related to the work function of the metal), are absorbed by electrons within the metal, and if the energy is equal to or greater than the work function of the metal, the electrons can escape the surface, with any energy in excess of the work function contributing to the kinetic energy of the emitted electron.