Question

The rate of emission of thermions is temperature of the surface emitting thermions.

• A. directly proportional to
• B. independent of
• C. inversely proportional to
• D. None of these

Answer 1

Answer: (A)

directly proportional to

Thermal energy given to the charge carriers overcome the work function of the metal surface and thus flow of charge carriers takes place from the metal surface. More the thermal energy given to the metal surface by increasing its temperature, more easily the charge carriers overcome the work function and thus more will be the rate of emission of thermions. Hence rate of emission of thermions is directly proportional to the temperature of the surface emitting thermions.