(physics) The energy-emitting propensity of a surface, usually measured at a specific wavelength.
Used in a Sentence
emissivity
Definition, parts of speech, synonyms, and sentence examples for emissivity.
Editorial note
The reason is that you usually don't know the emissivity of the surface that precisely, or for that matter its reflectivity.
Examples17
Definitions1
Parts of speech1
Quick take
(physics) The energy-emitting propensity of a surface, usually measured at a specific wavelength.
Meaning at a glance
The clearest senses and uses of emissivity gathered in one view.
Definitions
Core meanings and parts of speech for emissivity.
noun
(physics) The energy-emitting propensity of a surface, usually measured at a specific wavelength.
Example sentences
The reason is that you usually don't know the emissivity of the surface that precisely, or for that matter its reflectivity.
Next up in the equation is surface emissivity which we’ve got a lot of experience in the automotive sector.
Given the solar constant 1361 W/m^2, you can calculate the temperature range based on the emissivity and absorptivity.
The thermal radiation panels would be optimized for emissivity 1, the opposite of whats inside the vacuum flask.
Infrared thermometers like the one used in this article are (typically) calibrated for an emissivity of 0.95.
Basically you concentrate the heat into a high emissivity high temperature material that’s facing deep space and is shaded.
Yes and they mirror the glass (emissivity nearer to ~0) precisely because thermal radiation would occur otherwise.
The deforestation graph only seems to account for the difference in emissivity between forest and grassland.
Thermal radiation is proportional to the fourth power of temperature and proportional to emissivity (which is between 0 and 1).
If you use one on a material with a lower emissivity, it'll give inaccurate readings.
Lets pretend you are correct and thus thermally blackened glass (emissivity 1) inside the vacuum flask would be fine according to you.
Let's assume a single planar radiator, with emissivity ~1 over the thermal infrared range.
Quote examples
Quote: "emissivity higher than 0.99 over a wide range of wavelengths".
Even for a simple sphere, if we give it different surface roughnesses on the sun-facing side and the "night" side, it can have dramatically different emissivity.
"High emissivity, high temperature" sounds good on paper, but to create that temperature gradient within your spacecraft the way you want costs a lot of energy.
"emissivity higher than 0.99 over a wide range of wavelengths" is basically code for "it's, like, super black" The limiting factor isn't the emissivity, it's that you're having to rely on radiation as your only cooling mechanism.
Proper noun examples
Emissivity isn't going past 1 in that equation, and you're going to have a very hard time getting your radiator to be hotter than your heat source.
Frequently asked questions
Short answers drawn from the clearest meanings and examples for this word.
How do you use emissivity in a sentence?
The reason is that you usually don't know the emissivity of the surface that precisely, or for that matter its reflectivity.
What does emissivity mean?
(physics) The energy-emitting propensity of a surface, usually measured at a specific wavelength.
What part of speech is emissivity?
emissivity is commonly used as noun.