Emission coefficient

Emission coefficient is a coefficient in the power output per unit time of an electromagnetic source, a calculated value in physics. It is also used as a measure of environmental emissions (by mass) per MWh of electricity generated, see: Emission factor.

Additional recommended knowledge

Don't let static charges disrupt your weighing accuracy

Essential Laboratory Skills Guide

Recognize and detect the effects of electrostatic charges on your balance

Scattering of light

In Thomson scattering a charged particle emits radiation under incident light. The particle may be an ordinary atomic electron, so emission coefficients have practical applications.

If X dV dΩ dλ is the energy scattered by a volume element dV into solid angle dΩ between wavelengths λ and λ+dλ per unit time then the Emission coefficient is X.

The values of X in Thomson scattering can be predicted from incident flux, the density of the charged particles and their Thomson differential cross section (area/solid angle).

Spontaneous Emission

A warm body emitting photons has a monochromatic emission coefficient relating its temperature and total power radiation, this is sometimes called the second "Einstein coefficient", and can be deduced from quantum mechanical theory.

See also

• The Diode equation includes the emission coefficient
• Plasma physics.
• An emission coefficient is also given for ballistic secondary electron emission.
• Luminous coefficient