Emissivity: Difference between revisions

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imported>Niek Sanders
(Defn of emissivity.)
 
imported>Niek Sanders
m (Wiki link to irradiance.)
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Emissivity is a term in [[radiometry]].  It is the ratio between the observed exitance and ideal [[Black-body_radiation|blackbody exitance]]:
Emissivity is a term in [[radiometry]].  It is the ratio between the observed [[Irradiance|exitance]] and ideal [[Black-body_radiation|blackbody exitance]]:


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Revision as of 14:14, 18 September 2007

Emissivity is a term in radiometry. It is the ratio between the observed exitance and ideal blackbody exitance:

Note that emissivity is a unitless quantity in the range [0,1]. It normally varies as a function of wavelength. Objects with a uniform emissivity are often called gray bodies.