Question

The characteristics which a material should possess to act as a good thermionic emitter are :

• A. high work function and high melting point
• B. high work function and low melting point
• C. low work function and high melting point
• D. low work function and low melting point

Answer 1

The correct option is C low work function and high melting point

C

The characters in which a good thermonic emitter posses ore low work function and high melting point. Work function is the energy required to remove an electron from the metal surface. For a good thermonic emitter only low energy is needed for remove electrons from the metal surface and also it must posses high melting point so that the metal will not melt even if high temperature is applied.