Babylon 10
The world's best online dictionary

Download it's free

Definition of Emissivity

Babylon English

ability to emit (Physics)
Emissivity Definition from Language, Idioms & Slang Dictionaries & Glossaries
Webster's Revised Unabridged Dictionary (1913)
(n.)
Tendency to emission; comparative facility of emission, or rate at which emission takes place, as of heat from the surface of a heated body.
  
Webster's Revised Unabridged Dictionary (1913), edited by Noah Porter. About
hEnglish - advanced version

emissivity
\em`is*siv"i*ty\ (?), n. tendency to emission; comparative facility of emission, or rate at which emission takes place; specif. (physics), the rate of emission of heat from a bounding surface per degree of temperature difference between the surface and surrounding substances (called by fourier external conductivity).
emissivity
\em`is*siv"i*ty\ (?), n. tendency to emission; comparative facility of emission, or rate at which emission takes place, as of heat from the surface of a heated body.

Emissivity Definition from Science & Technology Dictionaries & Glossaries
Telecommunication Standard Terms
The ratio of power radiated by a substance to the power radiated by a blackbody at the same temperature. (188 )
Electronics Terminology
The ratio of the radiant energy emitted by a source to the radiant energy of a perfect radiating surface (black box) having an equivalent surface area with all other relevant conditions being the same.
WEATHER&METEOROLOGY
How well a system radiates at a given wavelength.
Technical English by wpv
The ratio of energy emitted by an object to the energy emitted by a blackbody at the same temperature. The emissivity of an object depends upon its material and surface texture; a polished metal surface can have an emissivity around 0.2 and a piece of wood can have an emissivity around 0.95.
Emissivity Definition from Encyclopedia Dictionaries & Glossaries
Wikipedia English - The Free Encyclopedia
The emissivity of the surface of a material is its effectiveness in emitting energy as thermal radiation. Thermal radiation is light, but for objects near room temperature this light is infrared and isn't visible to human eyes. The thermal radiation from very hot objects (see photograph) is easily visible to the eye. Quantitatively, emissivity is the ratio of the thermal radiation from a surface to the radiation from an ideal black surface at the same temperature. The ratio varies from 0 to 1. At room temperature, the surface of a black object emits thermal radiation at the rate of 418 watts per square meter; real objects with emissivities less than 1.0 emit radiation at correspondingly lower rates.

See more at Wikipedia.org...
© This article uses material from Wikipedia® and is licensed under the GNU Free Documentation License and under the Creative Commons Attribution-ShareAlike License