Spectra definition

Spectra





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3 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Spectrum \Spec"trum\, n.; pl. {Spectra}. [L. See {Specter}.]
     1. An apparition; a specter. [Obs.]
        [1913 Webster]
  
     2. (Opt.)
        (a) The several colored and other rays of which light is


            composed, separated by the refraction of a prism or
            other means, and observed or studied either as spread
            out on a screen, by direct vision, by photography, or
            otherwise. See Illust. of {Light}, and {Spectroscope}.
        (b) A luminous appearance, or an image seen after the eye
            has been exposed to an intense light or a strongly
            illuminated object. When the object is colored, the
            image appears of the complementary color, as a green
            image seen after viewing a red wafer lying on white
            paper. Called also {ocular spectrum}.
            [1913 Webster]
  
     {Absorption spectrum}, the spectrum of light which has passed
        through a medium capable of absorbing a portion of the
        rays. It is characterized by dark spaces, bands, or lines.
        
  
     {Chemical spectrum}, a spectrum of rays considered solely
        with reference to their chemical effects, as in
        photography. These, in the usual photogrophic methods,
        have their maximum influence at and beyond the violet
        rays, but are not limited to this region.
  
     {Chromatic spectrum}, the visible colored rays of the solar
        spectrum, exhibiting the seven principal colors in their
        order, and covering the central and larger portion of the
        space of the whole spectrum.
  
     {Continous spectrum}, a spectrum not broken by bands or
        lines, but having the colors shaded into each other
        continously, as that from an incandescent solid or liquid,
        or a gas under high pressure.
  
     {Diffraction spectrum}, a spectrum produced by diffraction,
        as by a grating.
  
     {Gaseous spectrum}, the spectrum of an incandesoent gas or
        vapor, under moderate, or especially under very low,
        pressure. It is characterized by bright bands or lines.
  
     {Normal spectrum}, a representation of a spectrum arranged
        upon conventional plan adopted as standard, especially a
        spectrum in which the colors are spaced proportionally to
        their wave lengths, as when formed by a diffraction
        grating.
  
     {Ocular spectrum}. See {Spectrum}, 2
        (b), above.
  
     {Prismatic spectrum}, a spectrum produced by means of a
        prism.
  
     {Solar spectrum}, the spectrum of solar light, especially as
        thrown upon a screen in a darkened room. It is
        characterized by numerous dark lines called Fraunhofer
        lines.
  
     {Spectrum analysis}, chemical analysis effected by comparison
        of the different relative positions and qualities of the
        fixed lines of spectra produced by flames in which
        different substances are burned or evaporated, each
        substance having its own characteristic system of lines.
        
  
     {Thermal spectrum}, a spectrum of rays considered solely with
        reference to their heating effect, especially of those
        rays which produce no luminous phenomena.
        [1913 Webster]

From WordNet (r) 2.0 [wn]:

  spectrum
       n 1: an ordered array of the components of an emission or wave
       2: broad range of related values or qualities or ideas or
          activities
       [also: {spectra} (pl)]

From WordNet (r) 2.0 [wn]:

  spectra
       See {spectrum}

















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