emissivity

American  

[em-uh-siv-i-tee, ee-muh-] / ˌɛm əˈsɪv ɪ ti, ˈi mə- /

noun

Thermodynamics.

1. 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 British  

/ ˌɛm-, ɪmɪˈsɪvɪtɪ /

noun

1.  ε.  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

---

Etymology

Origin of emissivity

First recorded in 1875–80; emissive + -ity

Example Sentences

Efficient cooling requires high reflectivity in the former range to minimise the solar heat gain and high emissivity in the latter range to maximise the radiative heat dissipation.

From Science Daily

VERITAS, short for Venus Emissivity, Radio Science, InSAR, Topography & Spectroscopy, is to launch about a year before DAVINCI+.

From New York Times

Low-e, for “low emissivity,” refers to a microscopically thin coating of metallic particles that reflect some wavelengths of light while allowing most of the visible wavelengths to pass through.

From Washington Post

The unpainted metal absorbs a significant amount of solar energy in the desert environment, and black paint would increase its ability to retain heat — or “emissivity” — by less than 10 percent, according to Rick Duncan, a materials engineer who works for trade associations and specializes in rooftop coatings.

From Washington Post

The scales over the nonliving wing parts, which are not as easily damaged by heat, do not have such high “thermal emissivity.”

From Scientific American