Incandescence


Incandescence

Incandescence is the emission of light (visible electromagnetic radiation) from a hot body due to its temperature. [cite book | title = Treatise on Heat
author = Dionysius Lardner | publisher = Longman, Rees, Orme, Brown, Green & Longman | year = 1833 | url = http://books.google.com/books?id=jjYIAAAAIAAJ&pg=PA341&dq=incandescence+becomes-luminous&lr=&as_brr=1&ei=Hyk7SMu8FJHUsgOf28XBCw | quote = The state in which a heated body, naturally incapable of emitting light, becomes luminous, is called a state of "incandescence".
] The term derives from the verb "incandesce," to grow white. [cite book | title = An Introduction to Practical Chemistry, Including Analysis | author = John E. Bowman | edition = Second American edition | publisher = Philadelphia: Blanchard and Lea | year = 1856 | url = http://books.google.com/books?id=ffTcf4FGOx4C&pg=PA283&dq=incandesce+date:0-1860&lr=&as_brr=1&ei=vy07SMLWOYvAsgP3vPHPDA ]

The incandescence of a theoretically perfectly black object is known as black body radiation, which is described by relatively simple mathematical equations. For a black body, the distribution of energy emissions across the electromagnetic spectrum is described by Planck's law. The total power emitted by radiation from a black body is given by the Stefan–Boltzmann law. Wien's displacement law predicts the wavelength of peak emission.

Incandescence occurs in incandescent light bulbs, because the filament resists the flow of electrons. This resistance heats the filament to a temperature where part of the radiation falls in the visible spectrum. The majority of radiation, however, is emitted in the invisible infrared part of the spectrum, which is why incandescent light bulbs are inefficient. [cite book | title = Illumination and Photometry | author = William Elgin Wickenden | publisher = McGraw-Hill | year = 1910 | url = http://books.google.com/books?id=gVZDAAAAIAAJ&pg=PA3&dq=incandescent+low-efficiency+blackbody&lr=&as_brr=1&ei=idBGSJ-RMJGosgPKq42wDQ ]

Fluorescent lamps do not function by means of incandescence, rather by a combination of thermionic emission and atomic excitation due to collision with high energy electrons. In an incandescent lamp, only the electrons at the top of the band can participate. Higher temperature can increase efficiency but we do not have materials that can withstand much higher temperature.

See also

*Incandescent light bulb
*List of light sources

References


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  • incandescence — [ ɛ̃kɑ̃desɑ̃s ] n. f. • 1779; de incandescent ♦ État d un corps incandescent. Métal chauffé jusqu à l incandescence. ⇒ 2. blanc (à blanc). Être en incandescence. ⇒ brûler. Lampe à incandescence, qui éclaire par un filament porté à incandescence.… …   Encyclopédie Universelle

  • Incandescence — In can*des cence, n. [Cf. F. incandescence.] A white heat, or the glowing or luminous whiteness of a body caused by intense heat. [1913 Webster] …   The Collaborative International Dictionary of English

  • incandescence — (n.) 1650s, figurative, state of being inflamed, from INCANDESCENT (Cf. incandescent) + ENCE (Cf. ence). Literal use from 1794 …   Etymology dictionary

  • Incandescence — L incandescence est un phénomène physique universel. L incandescence est une émission de lumière due à la chaleur. En effet, tout corps chauffé suffisamment émet des rayonnements électromagnétiques dans le spectre visible (et ce donc, à partir d… …   Wikipédia en Français

  • incandescence — (in can dè ssan s ) s. f. 1°   État d un corps échauffé jusqu à devenir blanc et lumineux. •   Cette couleur blanche, qui sort de tous les corps en incandescence et vient frapper nos yeux, est l évaporation de cette flamme dense qui environne le… …   Dictionnaire de la Langue Française d'Émile Littré

  • INCANDESCENCE — s. f. État d un corps qui est échauffé et pénétré de feu jusqu à devenir blanc. Barre de fer échauffée jusqu à l incandescence. Ce métal est dans l état d incandescence …   Dictionnaire de l'Academie Francaise, 7eme edition (1835)

  • INCANDESCENCE — n. f. état d’un corps qui est chauffé à blanc. Barre de fer échauffée jusqu’à l’incandescence. Lampe à incandescence …   Dictionnaire de l'Academie Francaise, 8eme edition (1935)

  • incandescence — kaitinimas statusas T sritis automatika atitikmenys: angl. heating; incandescence vok. Beheizung, f; Erhitzen, n; Erwärmen, n; Glühen, n; Heizung, f rus. нагрев, m; нагревание, n; накал, m; накаливание, n pranc. chauffage, m; chauffe, f;… …   Automatikos terminų žodynas

  • incandescence — kaitinimas statusas T sritis fizika atitikmenys: angl. heating; incandescence vok. Erhitzung, f; Glühen, n; Heizung, f rus. нагрев, m; накал, m; накаливание, n pranc. chauffage, m; chauffe, f; incandescence, f …   Fizikos terminų žodynas

  • incandescence — kaitinimas statusas T sritis Standartizacija ir metrologija apibrėžtis Kūno temperatūros didinimas (daugiau kaip 100 ºC). atitikmenys: angl. heating vok. Erwärmung, f; Glühen, n; Heizung, f rus. нагрев, m; накаливание, n; разогрев, m pranc.… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas


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