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fluorescence - 9 dictionary results

fluo⋅res⋅cence

[floo-res-uhns, flaw-, floh-]
–noun Physics, Chemistry.
1. the emission of radiation, esp. of visible light, by a substance during exposure to external radiation, as light or x-rays. Compare phosphorescence (def. 1).
2. the property possessed by a substance capable of such emission.
3. the radiation so produced.

Origin:
1852; fluor(spar) + -escence, on the model of opalescence, in reference to the mineral's newly discovered property
fluo·res·cence   (flŏŏ-rěs'əns, flô-, flō-)   
n.  
  1. The emission of electromagnetic radiation, especially of visible light, stimulated in a substance by the absorption of incident radiation and persisting only as long as the stimulating radiation is continued.
  2. The property of emitting such radiation.
  3. The radiation so emitted.

[fluor(spar) + -escence.]

Fluorescence

Flu`o*res"cence\, n. [From Fluor.] (Opt.) That property which some transparent bodies have of producing at their surface, or within their substance, light different in color from the mass of the material, as when green crystals of fluor spar afford blue reflections. It is due not to the difference in the color of a distinct surface layer, but to the power which the substance has of modifying the light incident upon it. The light emitted by fluorescent substances is in general of lower refrangibility than the incident light. --Stockes.

Fluorescence

Flu`o*res"cence\, n. A property possessed by fluor spar, uranium glass, sulphide of calcium, and many other substances, of glowing without appreciable rise of temperature when exposed to light or to ultra-violet rays, cathode rays, X rays, etc.

fluorescence

The emission of light from an object as a result of bombardment by other kinds of electromagnetic radiation, such as x-rays or ultraviolet rays. Fluorescent materials may appear one color when bathed in visible light and another color when exposed to other kinds of electromagnetic radiation.

Note: “Black light” depends on fluorescence for its effects.

fluorescence 
1852, "glowing in ultraviolet light," coined by Eng. mathematician and physicist Sir George G. Stokes (1819-1903) from fluorspar (see fluorine), because in it he first noticed the phenomenon, + ending -escence from opalescence, phosphorescence. The fluorescent electric lamp patent was applied for in 1896 by Thomas A. Edison, but such lights were rare before 1938.

Main Entry: flu·o·res·cence
Pronunciation: -'es-&n(t)s
Function: noun
: luminescence that is caused by the absorption ofradiation at one wavelength followed by nearly immediate reradiation usually at a different wavelength and that ceases almost immediately when the incident radiation stops; also : theradiation emitted —flu·o·res·cent /-'es-&nt/ adjective

fluorescence fluo·res·cence (fl&oobreve;-rěs'əns, flô-)
n.

  1. The emission of electromagnetic radiation, especially of visible light, stimulated in a substance by the absorption of incident radiation and persisting only as long as the stimulating radiation is continued.
  2. The property of emitting such radiation.

fluo·res'cent adj.

fluorescence   (fl-rěs'əns)  Pronunciation Key 
  1. The giving off of light by a substance when it is exposed to electromagnetic radiation, such as visible light or x-rays. As long as electromagnetic radiation continues to bombard the substance, electrons in the fluorescent material become excited but return very quickly to lower energy, giving off light, always of the same frequency. Fluorescent dyes are often used in microscopic imaging, where different dyes can penetrate and illuminate different parts of the sample being examined, helping to distinguish its structures. Compare phosphorescence.
  2. The light produced in this way.

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