Question

Deffine power of black body and coefficient of emission

Answer 1

Answer:

Coefficient of emission of a body is the ratio of the emissive power of the body at a given temperature to the emissive power of a perfectly black body at the same temperature.

Answer 2

Emittance. Emittance (or emissive power) is the total amount of thermal energy emitted per unit area per unit time for all possible wavelengths. Emissivity of a body at a given temperature is the ratio of the total emissive power of a body to the total emissive power of a perfectly black body at that temperature.

The emission of atomic line radiation at frequency ν may be described by an emission coefficient with units of energy/(time × volume × solid angle). ε dt dV dΩ is then the energy emitted by a volume element in time into solid angle .

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