un·du·la·to·ry theory /ˈənʤələˌtorɪ, ˈənd(j)ələ, ˌtɔrɪ-/ 名詞
 惠根(氏)學說,波動學說(光線)


 Un·du·la·to·ry a.  Moving in the manner of undulations, or waves; resembling the motion of waves, which successively rise or swell rise or swell and fall; pertaining to a propagated alternating motion, similar to that of waves.
 Undulatory theory, or Wave theory (of light) Opt., that theory which regards the various phenomena of light as due to undulations in an ethereal medium, propagated from the radiant with immense, but measurable, velocities, and producing different impressions on the retina according to their amplitude and frequency, the sensation of brightness depending on the former, that of color on the latter.  The undulations are supposed to take place, not in the direction of propagation, as in the air waves constituting sound, but transversely, and the various phenomena of refraction, polarization, interference, etc., are attributable to the different affections of these undulations in different circumstances of propagation.  It is computed that the frequency of the undulations corresponding to the several colors of the spectrum ranges from 458 millions of millions per second for the extreme red ray, to 727 millions of millions for the extreme violet, and their lengths for the same colors, from the thirty-eight thousandth to the sixty thousandth part of an inch. The theory of ethereal undulations is applicable not only to the phenomena of light, but also to those of heat.

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 Wave, n.
 1. An advancing ridge or swell on the surface of a liquid, as of the sea, resulting from the oscillatory motion of the particles composing it when disturbed by any force their position of rest; an undulation.
    The wave behind impels the wave before.   --Pope.
 2. Physics A vibration propagated from particle to particle through a body or elastic medium, as in the transmission of sound; an assemblage of vibrating molecules in all phases of a vibration, with no phase repeated; a wave of vibration; an undulation.  See Undulation.
 3. Water; a body of water.  [Poetic] “Deep drank Lord Marmion of the wave.”
 Build a ship to save thee from the flood,
 I 'll furnish thee with fresh wave, bread, and wine.   --Chapman.
 4. Unevenness; inequality of surface.
 5. A waving or undulating motion; a signal made with the hand, a flag, etc.
 6. The undulating line or streak of luster on cloth watered, or calendered, or on damask steel.
 7. Something resembling or likened to a water wave, as in rising unusually high, in being of unusual extent, or in progressive motion; a swelling or excitement, as of feeling or energy; a tide; flood; period of intensity, usual activity, or the like; as, a wave of enthusiasm; waves of applause.
 Wave front Physics, the surface of initial displacement of the particles in a medium, as a wave of vibration advances.
 Wave length Physics, the space, reckoned in the direction of propagation, occupied by a complete wave or undulation, as of light, sound, etc.; the distance from a point or phase in a wave to the nearest point at which the same phase occurs.
 Wave line Shipbuilding, a line of a vessel's hull, shaped in accordance with the wave-line system.
 Wave-line system, Wave-line theory Shipbuilding, a system or theory of designing the lines of a vessel, which takes into consideration the length and shape of a wave which travels at a certain speed.
 Wave loaf, a loaf for a wave offering. --Lev. viii. 27.
 Wave moth Zool., any one of numerous species of small geometrid moths belonging to Acidalia and allied genera; -- so called from the wavelike color markings on the wings.
 Wave offering, an offering made in the Jewish services by waving the object, as a loaf of bread, toward the four cardinal points. --Num. xviii. 11.
 Wave of vibration Physics, a wave which consists in, or is occasioned by, the production and transmission of a vibratory state from particle to particle through a body.
 Wave surface. (a) Physics A surface of simultaneous and equal displacement of the particles composing a wave of vibration. (b) Geom. A mathematical surface of the fourth order which, upon certain hypotheses, is the locus of a wave surface of light in the interior of crystals. It is used in explaining the phenomena of double refraction.  See under Refraction.
 Wave theory. Physics See Undulatory theory, under Undulatory.

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 undulatory theory
      n : (physics) the theory that light is transmitted as waves
          [syn: wave theory, wave theory of light] [ant: {corpuscular
          theory, corpuscular theory]