Question

What is emissive power ?​

Answer 1

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Emissive Power :-

Amount of radiation emitted by a surface per unit time per unit area is called Emissive Power of that surface.

★ Emissive power , E = ∆Q/A∆t

where, ∆Q = Amount of Energy , ∆t = change in time , A = Surface Area

★ Unit of Emissive power is J/m^2sec or watt/m^2.

Answer 2

Answer:

(1) Emissive power or radiant power of a body (symn-

bol, R): The emissive power or radiant power of a

body at a given temperature is defined as the

quantity of radiant energy emitted by the body per

unit time per unit surlace area of the body at that

temperature.

(2) Coefficient of emission (or emissivity) of a body

(symbol, e): The coefficient of emission (or

emissivity) of a body is defined as the ratio of the

emissive power of the body (R) to the emissive

power of a perfect blackbody (R,) at the same

temperature as that of the body.