Question

State two characteristics of a good thermion emitter.

Answer 1

When a filament is heated to some extent, electron gain the thermal energy which breaks the interaction between the electron and the nucleus. This results in the emission of electron from the surface of the filament. The filament is, so generally, called as thermion emitter.

Two characteristics of thermion emitter :

(1) : Thermion emitter should have high melting point so that it does not melt even at high temperature..

(2) : Work function of thermion emitter should be low so that less heat energy is required to emit electron from its surface.