Thermions are

Explain the emission of electrons from a metal. Define work function. Write its unit,and state the factors upon which the work function of a metal depends.

In an electron gun,the control grid is kept at a negative potential with respect to the cathode because...

Who evaluated the mass of the electron indirectly with the help of its charge?

Cathode rays travelling from east to west enter into a region of an electric field directed towards north to south in the plane of the paper. The deflection of cathode rays is towards:

An oxide-coated filament is useful in vacuum tubes because essentially: