incandescence
American Heritage Dictionary:
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in·can·des·cence
(ĭn'kən-dĕs'əns) 
n.
n.
- The emission of visible light by a hot object.
- The light emitted by an incandescent object.
- A high degree of emotion, intensity, or brilliance.
McGraw-Hill Science & Technology Encyclopedia:
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Incandescence
The emission of visible radiation by a hot body. A theoretically perfect radiator, called a blackbody, will emit radiant energy according to Planck's radiation law at any temperature. Prediction of the visual brightness requires additional consideration of the sensitivity of the eye, and the radiation will be visible only for temperatures of the blackbody which are above some minimum. The relation between brightness and temperature is plotted in the illustration. As shown, the minimum temperature for incandescence for the dark-adapted eye is about 390°C (730°F). Under these ideal observing conditions, the incandescence appears as a colorless glow. The dull red light commonly associated with incandescence of objects in a lighted room requires a temperature of about 500°C (930°F). See also Blackbody; Heat radiation; Incandescent lamp; Vision.
Relation between brightness of blackbody and temperature.
McGraw-Hill Dictionary of Architecture & Construction:
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incandescence
The emission of visible light as a result of heating.
Electronics Dictionary:
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incandescence
State of a material when heated to the point where it emits light. (red hot or white hot).
Random House Word Menu:
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categories related to 'incandescence'
- Optics - incandescence: emission of light due to thermal excitation
- Physical Properties and Changes - incandescence: emission of light by a substance as a result of raising it to a high temperature
Wikipedia on Answers.com:
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Incandescence
For the science fiction novel with the same name, see Incandescence (novel).
Incandescence is the emission of light (visible electromagnetic radiation) from a hot body as a result of its temperature.[1] The term derives from the Latin verb incandescere, to glow white.[2]
Incandescence is a special case of thermal radiation. Incandescence usually refers specifically to visible light, while thermal radiation refers also to infrared or any other electromagnetic radiation.
For a detailed discussion of the intensity and spectrum (color) of incandescence, see the article: thermal radiation.
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Observation and use
Main article: Thermal radiation
In practice, virtually all solid or liquid substances start to glow around 798 K (525 °C), with a very dull red color, when no chemical reactions take place that produce light as a result of an exothermic process. This limit is called the Draper point. The incandescence does not vanish below that temperature, but it is too weak in the visible spectrum to be perceivable.
At higher temperatures, the substance becomes brighter and its color changes from red towards white and finally blue.
Incandescence is exploited in incandescent light bulbs, in which a filament is heated to a temperature at which a fraction of the radiation falls in the visible spectrum. The majority of the radiation however, is emitted in the infrared part of the spectrum, rendering incandescent lights relatively inefficient as a light source.[3] If the filament could be made hotter, efficiency would increase; however, there are currently no materials able to withstand such temperatures which would be appropriate for use in lamps.
More efficient light sources, such as fluorescent lamps and LEDs, do not function by incandescence.
Sunlight is the incandescence of the "white hot" surface of the sun.
Figurative use
The word incandescent is also used figuratively to describe a person who is so angry that they are imagined to glow or burn red hot or white hot.[4]
See also
References
- ^ Dionysius Lardner (1833). Treatise on Heat. Longman, Rees, Orme, Brown, Green & Longman. http://books.google.com/?id=jjYIAAAAIAAJ&pg=PA341&dq=incandescence+becomes-luminous. "The state in which a heated body, naturally incapable of emitting light, becomes luminous, is called a state of incandescence."
- ^ John E. Bowman (1856). An Introduction to Practical Chemistry, Including Analysis (Second American ed.). Philadelphia: Blanchard and Lea. http://books.google.com/?id=ffTcf4FGOx4C&pg=PA283&dq=incandesce+date:0-1860.
- ^ William Elgin Wickenden (1910). Illumination and Photometry. McGraw-Hill. http://books.google.com/?id=gVZDAAAAIAAJ&pg=PA3&dq=incandescent+low-efficiency+blackbody.
- ^ Example 1:'...the stadium positively crackled with the incandescent anger of anguished supporters.' Mark Wilson, 'Rangers 1 Unirea 4', Daily Mail, 21 October 2009 [1]. Example 2: '...there's something very funny about incandescent anger.' Mark Fisher, 'Jerry has a cross to bear', The Scotsman, 5 March 2006 [2].
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The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
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McGraw-Hill Encyclopedia of Science and Technology. Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved.
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McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc. All rights reserved.
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