Class 12 NEET Physics Electromagnetic Waves Questions

Thermionic emission : When a metal is heated to a high temperature, the free electron gain kinetic energy and escape from the surface of the metal.
Secondary emission : When an electron strikes the surface of a metallic plate, it emits other electrons from the surface.
Photoelectric emission : Emission of electrons from the metal surface on irradiation with radiation of suitable frequency.
X -rays emission : They are due to transitions in the inner energy levels of the atom.