Photoelectric Current @ Meritnation

The video describes an experimental set up to make a systematic study of photoelectric effect. Light of appropriate frequency is made incident on a metal surface (cathode). The emitted electrons are collected by a collector plate (anode) which is kept at a positive potential. A graph between photoelectric current and positive potential of the collector is drawn. A saturation point called ‘Saturation current’ is obtained above which photocurrent doesn’t increase any further with increase in collector potential. The collector potential is then reversed and corresponding photocurrent is observed. There is a sharp decrease in photocurrent with increase in negative potential of the collector. The current completely stops at a certain negative potential of the collector called ‘stopping potential’.

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