Question

How can electron be made to leave the metal surface?(State any two ways).

Answer 1

If we want to remove the electron from the metal surface, we have to give some energy to the electron which would break the force of interaction between the nucleus and the electron so that it can leave the metal surface.

There are two ways to make the electrons to leave the metal surface :

(1) : Photoelectric effect : A light having energy greater than the work function of the metal is incidented on it and in result the photoelectrons are emitted from the metal surface.

(2) : Thermionic emission : The metal surface is heated which gives sufficient energy to the electrons and so the electron breaks the interaction with the nucleus and leaves the metal surface.