In photoelectric effect, why should the photoelectric current current increases as the intensity of monochromatic . . .

Question : In photoelectric effect, why should the photoelectric current current increases as the intensity of monochromatic radiation incident on a photosensitive surface is increased? Explain.

Doubt by Safir

Solution : 

When the intensity of radiation incident on the photosensitive surface is increased then number of photons emitted per second per unit area also increases. These photons helps in ejecting more electrons from the photosensitive metal surface. Higher the number of electrons, higher will be the photoelectric current. This is why photoelectric current increases when intensity of radiation is increased.