emissivity

noun

emis·​siv·​i·​ty ˌe-mə-ˈsi-və-tē How to pronounce emissivity (audio)
ˌē-ˌmi-ˈsi-
plural emissivities
: the relative power of a surface to emit heat by radiation : the ratio of the radiant energy emitted by a surface to that emitted by a blackbody at the same temperature

Examples of emissivity in a Sentence

Recent Examples on the Web
These examples are automatically compiled from online sources to illustrate current usage. Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Concrete, for example, is rated at 0.85, brick can range between 0.73 and 0.93 depending on its composition, and bare metals like brass can have emissivity values as low as 0.03. Joan Meiners, USA TODAY, 10 Sep. 2024 This heat exchange depends on the properties of the TPV emitter, such as its emissivity and temperature, the optical properties of the cell, and other experimental conditions. IEEE Spectrum, 21 Feb. 2024 So emissivity is essentially the opposite of reflectivity. Rhett Allain, WIRED, 25 Aug. 2023 Both reflectivity and emissivity depend on the wavelength of light. Rhett Allain, WIRED, 25 Aug. 2023 At the base Premium level, the roof has a special coating called low-e, or low emissivity, to keep the interior cool by blocking some wavelengths of light. Kristin Shaw, Popular Science, 13 Mar. 2023 Finally, there is that last symbol—ε this is called the emissivity. WIRED, 3 Feb. 2023 An object that's a perfect thermal emitter has an emissivity of 1, and one that doesn't produce any thermal radiation has a value of 0. WIRED, 3 Feb. 2023 An elevation model of Idunn Mons on Venus, with thermal emissivity data overlain on the surface. Nathaniel Scharping, Discover Magazine, 18 Oct. 2016

Word History

First Known Use

1880, in the meaning defined above

Time Traveler
The first known use of emissivity was in 1880

Dictionary Entries Near emissivity

Cite this Entry

“Emissivity.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/emissivity. Accessed 5 Nov. 2024.

Medical Definition

emissivity

noun
emis·​siv·​i·​ty ˌem-ə-ˈsiv-ət-ē How to pronounce emissivity (audio) ˌē-ˌmis-ˈiv- How to pronounce emissivity (audio)
plural emissivities
: the relative power of a surface to emit heat by radiation : the ratio of the radiant energy emitted by a surface to that emitted by a blackbody at the same temperature
Last Updated: - Updated example sentences
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