Answer
Emissivity: proportion of termic radiation emitted by a surface or a body.
Absorptivity: proportion of the termic radiation incident on a surface that is absorbed.
Kirchhoff's law of radiation" A body or surface in termodinamic equilibrium has the same emissivity and absorptivity"
Work Step by Step
The emissivity is the proportion of termic radiation emitted by a surface or a body because of its temperature.
Absorptivity is the proportion of the termic radiation incident on a surface that is absorbed.
Kirchhoff's law of radiation states that a body or surface in termodinamic equilibrium (termic, mechanic and chemical equilibrium) has the same emissivity and absorptivity.
