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Re: Radius Of Curvature

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Posted by Rick Crockett on November 8, 2000 17:36:45 UTC

Hi Charles:

Simple principle really, the angle of reflectance (or deflection) is twice the angle of incidence.

If a photon hits a mirror dead on it is reflected directly back. If it hits at any angle, it will be reflected back at an angle of twice that of the incoming photon. Image a mirror and a line sticking straight out from it. If a photon hits the surface at a 15 angle from perpendicular it will be reflected (mirrored) back on the opposite side of perpendicular. This means that there is now 30 between the incoming path and the exit path.

Think of a circle of reflective material. Light from the center hits the side dead on. The center point is the radius of curvature. Now move that light source over 15. To reflect back to the RoC, the light would have to be deflected 15 but we know that instead it will be 30 and thus crossing a point half way between the surface and the RoC.

Hope this Helps,
-Rick

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