Skip to main content
emissivity

emissivity

3 9.9
How well a surface gives off heat as invisible waves
  • noun
  • /ˌɛmɪˈsɪvɪti/
  • Specialized
translation icon : emissividad
  • A low-emissivity material, with a rating of 0.02, can get very hot without giving off much infrared radiation.
  • low-emissivity
  • emissivity and surface

Examples

  • One has to know the true emissivity in order to sense temperature accurately.

    Blog text (18)
  • Likewise, Milgard Windows' low emissivity SunCoat Low-E windows filter the sun in the summer and reduce heat loss in the winter.

    Academic text (2006)
  • That is the emissivity, the thing we're trying to calculate.

  • So this is part of knowing the emissivity of the object that's under test.

  • "We supply a low-emissivity membrane that can get as hot as it wants without emitting heat," he said.

    Academic text (2000)
  • Between temperatures of 250 and 273 K, reasonable for snow, the emissivity is about 0.98.

    Blog text (18)
  • The Pyrofiber non-contact automatic emissivity-correcting infrared thermometer has multiple sensor heads for uniform temperature measurements.

    Academic text (2003)
  • D-series IR thermometers are reportedly certified to NIST-traceable accuracy on real surfaces of unknown emissivity.

    Academic text (1997)
  • The D-series of handheld IR scanners/thermometers have been certified to NIST-traceable accuracy on real surfaces of unknown emissivity.

    Academic text (1996)
  • Understanding the emissivity of different materials is crucial for designing efficient thermal systems.

Synonyms

emittance
vsemissivity
  • Specialized
1 8.2

A number that shows how well a surface gives off heat as radiation

is a specific efficiency measured against an ideal blackbody

Surface Forms

emissivity singular
emissivities plural

Morphology

emissivity = emissive (semi-transparent) = emiss + ive + ity

Forming the noun from the adjective 'emissive' by adding '-ity' yields the expected meaning 'the quality/state of being emissive'.

Etymology

The word emissivity comes from the Latin root emit and the ending -ivity, where emit means 'to send out'. So emissivity is about how well a surface can 'send out' heat as radiation.