emissivity

[ em-uh-siv-i-tee, ee-muh- ]

Phonetic (Standard)IPA

noun

, Thermodynamics.

the ability of a surface to emit radiant energy compared to that of a black body at the same temperature and with the same area.

emissivity

/ ˌɛm-; ɪmɪˈsɪvɪtɪ /

a measure of the ability of a surface to radiate energy; the ratio of the radiant flux emitted per unit area to that emitted by a black body at the same temperature ε

First recorded in 1875–80; emissive + -ity

Values which are commonly given for the surface emissivity must therefore be accepted with great reserve.

The emissivity increases with the temperature, else no state of thermal equilibrium could be reached.

Although these mantles emitted a brilliant light for a few hours, their light-emissivity was destroyed by carbonization.

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