radius of curvature(redirected from radii of curvature)
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radius of curvature(ray -dee-us) Symbol: r , R . The radius of the sphere whose surface contains the surface of a spherical mirror, lens, or wavefront. The curvature of the mirror, etc., is given by the reciprocal of the radius of curvature, i.e. by 1/r . The radius of curvature of a mirror is twice its focal length, f . That of a lens is given by
1/f = (n – 1)(1/r 1 – 1/r 2 )where n is the refractive index; it is assumed that, in the direction of light travel, the radii, r 1 and r 2, for the convex and concave lens surfaces are positive and negative, respectively.
radius of curvature[′rād·ē·əs əv ′kər·və·chər]
The radius of the circle of curvature at a point of a curve.