What is photoelectric effect ? Explain effect of intensity on photoelectric current.

Explanation

Photoelectric effect:
(i) Variation of the current with intensity of incident radiation. Keep the collecting electrode at sufficient positive potential with respect to photosensitive plate P. Use incident light of fixed frequency (or colour). When intensity of light is slowly increased, the current also increases. The graph between intensity and current comes out to be linear (straight line). Therefore the number of photoelectrons emitted per second from a photosensitive plate is directly proportional to the intensity of incident radiations as shown in figure.