State two characteristics of the substance used as thermionic emitter.

1.	State two characteristics of the substance used as thermionic emitter.
Answer» (i) The substance must have high melting point. (ii) The work function of the substance should be low so that electrons may be emitted even at low temperature.

Answer»

(i) The substance must have high melting point.

(ii) The work function of the substance should be low so that electrons may be emitted even at low temperature.

Discussion