World Library  
Flag as Inappropriate
Email this Article

Incandescence

Article Id: WHEBN0000213835
Reproduction Date:

Title: Incandescence  
Author: World Heritage Encyclopedia
Language: English
Subject: Luminescence, Centennial Light, Incandescent light bulb, Featured picture candidates/Metal, Carbon button lamp
Collection: Electromagnetic Radiation, Light Sources, Luminescence
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Incandescence

Hot metal work glows with visible light. This thermal radiation also extends into the infrared, invisible to the human eye and the camera the image was taken with, but an infrared camera could show it (See Thermography).
The incandescent metal embers of the spark used to light this Bunsen burner emit light ranging in color from white to orange to red or to blue. This change correlates with their temperature as they cool in the air. The flame itself is not incandescent, as its blue color comes from the quantized transitions that result from the oxidation of CH radicals.

Incandescence is the emission of electromagnetic radiation (including visible light) 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.

Contents

  • Observation and use 1
  • Figurative use 2
  • See also 3
  • References 4
  • External links 5

Observation and use

In practice, virtually all solid or liquid substances start to glow around 798 K (525 °C) (977 degrees F˚), with a mildly 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

Incandescence

References

  1. ^  
  2. ^ John E. Bowman (1856). An Introduction to Practical Chemistry, Including Analysis (Second American ed.). Philadelphia: Blanchard and Lea. 
  3. ^ William Elgin Wickenden (1910). Illumination and Photometry. McGraw-Hill. 
  4. ^ Example 1:'...the stadium positively crackled with the incandescent anger of anguished supporters.' Mark Wilson, 'Rangers 1 Unirea 4', Daily Mail, 21 October 2009 [3]. Example 2: '...there's something very funny about incandescent anger.' Mark Fisher, 'Jerry has a cross to bear', The Scotsman, 5 March 2006 [4].

External links

  • Figurative use: Rangers 1 Unirea-Urziceni 4 etc.
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.