Question

Describe in brief the different ways of electron emission from a metal surface.

Answer 1

Depending on the physical ways to provide the energy to the electrons to know them off the metal surface; there are following type of emissions:

• Thermionic emission: By heating to temperatures ~2000ºC provide thermal energy.
• Field emission: By establishing strong electric fields ~10⁶ V/m at the surface of a metal tip, provide electrical energy.
• Photo-electron emission: By shining radiation of suitable frequency (ultraviolet or visible) on a metal surface provide light energy.