Question

The phenomenon of photoelectric effect was first explained by

Answer 1

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J.J. Thomson observed that when light of a certain frequency strikes the surface of a metal, electrons are ejected from the cathode metal. They completed the circuit through the gas in the tube which was otherwise a non-conductor. This phenomenon is called photoelectric effect. Only a few metals show this effect under the action of more energetic ultraviolet light is a discharge tube at low voltage.

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