Angle of refraction
Refraction Re*frac"tion (r?*fr?k"sh?n), n. [F. r['e]fraction.] 1. The act of refracting, or the state of being refracted. [1913 Webster]

2. The change in the direction of ray of light, heat, or the like, when it enters obliquely a medium of a different density from that through which it has previously moved. [1913 Webster]

Refraction out of the rarer medium into the denser, is made towards the perpendicular. --Sir I. Newton. [1913 Webster]

3. (Astron.) (a) The change in the direction of a ray of light, and, consequently, in the apparent position of a heavenly body from which it emanates, arising from its passage through the earth's atmosphere; -- hence distinguished as atmospheric refraction, or astronomical refraction. (b) The correction which is to be deducted from the apparent altitude of a heavenly body on account of atmospheric refraction, in order to obtain the true altitude. [1913 Webster]

{Angle of refraction} (Opt.), the angle which a refracted ray makes with the perpendicular to the surface separating the two media traversed by the ray.

{Conical refraction} (Opt.), the refraction of a ray of light into an infinite number of rays, forming a hollow cone. This occurs when a ray of light is passed through crystals of some substances, under certain circumstances. Conical refraction is of two kinds; external conical refraction, in which the ray issues from the crystal in the form of a cone, the vertex of which is at the point of emergence; and internal conical refraction, in which the ray is changed into the form of a cone on entering the crystal, from which it issues in the form of a hollow cylinder. This singular phenomenon was first discovered by Sir W. R. Hamilton by mathematical reasoning alone, unaided by experiment.

{Differential refraction} (Astron.), the change of the apparent place of one object relative to a second object near it, due to refraction; also, the correction required to be made to the observed relative places of the two bodies.

{Double refraction} (Opt.), the refraction of light in two directions, which produces two distinct images. The power of double refraction is possessed by all crystals except those of the isometric system. A uniaxial crystal is said to be optically positive (like quartz), or optically negative (like calcite), or to have positive, or negative, double refraction, according as the optic axis is the axis of least or greatest elasticity for light; a biaxial crystal is similarly designated when the same relation holds for the acute bisectrix.

{Index of refraction}. See under {Index}.

{Refraction circle} (Opt.), an instrument provided with a graduated circle for the measurement of refraction.

{Refraction of latitude}, {longitude}, {declination}, {right ascension}, etc., the change in the apparent latitude, longitude, etc., of a heavenly body, due to the effect of atmospheric refraction.

{Terrestrial refraction}, the change in the apparent altitude of a distant point on or near the earth's surface, as the top of a mountain, arising from the passage of light from it to the eye through atmospheric strata of varying density. [1913 Webster]


The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • angle of refraction — n the angle between a refracted ray and the normal drawn at the point of incidence to the interface at which refraction occurs * * * the angle between a refracted ray and a line perpendicular to the refracting surface; see refraction …   Medical dictionary

  • angle of refraction — Physics, Optics. the angle between a refracted ray and a line drawn normal to the interface between two media at the point of refraction. See diag. under refraction. [1765 75] * * * …   Universalium

  • angle of refraction — noun the angle between a refracted ray and a line perpendicular to the surface between the two media at the point of refraction • Hypernyms: ↑angle …   Useful english dictionary

  • angle of refraction — an′gle of refrac′tion n. opt phs the angle between a refracted ray and a normal to the interface between two media at the point of refraction • Etymology: 1765–75 …   From formal English to slang

  • angle of refraction — noun the angle that a refracted ray of light makes with the perpendicular to the interfacial surface at the point of refraction …   Australian English dictionary

  • angle of refraction — Date: circa 1727 the angle between a refracted ray and the normal drawn at the point of incidence to the interface at which refraction occurs …   New Collegiate Dictionary

  • angle of refraction — noun The angle between the perpendicular and a ray refracted at a surface …   Wiktionary

  • angle of refraction — noun Physics the angle made by a refracted ray with a perpendicular to the refracting surface …   English new terms dictionary

  • Angle of incidence — is a measure of deviation of something from straight on , for example: in the approach of a ray to a surface, or the angle at which the wing or horizontal tail of an airplane is installed on the fuselage, measured relative to the axis of the… …   Wikipedia

  • angle of deviation — Optics. the angle equal to the difference between the angle of incidence and the angle of refraction of a ray of light passing through the surface between one medium and another of different refractive index. Also called deviation. [1825 35] * *… …   Useful english dictionary

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