(21-07-2011, 04:01 PM)smart paper boy Wrote: Electron Emission
Introduction
Thermionic emission
The phenomenon involves the effect of heat on the interaction between electricity and matter. This heat induced electron flow is called thermionic emission. The physical phenomena was well studied by Richardson from 1901 and he got Nobel prize in physics in 1929 for his work.
Expression for thermoionic current density J is given by Richardson equation.
J = A T2 e –ϕ / kT
Where ϕ - the work function of the material.
T-the absolute temperature
and A =4πemk2 / h3 = 1.6 ˣ 10 6 A m-2 k- is called the Rechardson’s constant.