Page 2 - Lesson note refraction by spherical lens
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Such lenses are called diverging lenses.
Terms related to spherical lenses
1. Centre of curvature
It is the centre point of arcs of the two spheres from which the given spherical lens
(concave or convex) is made. Since a lens constitutes two spherical surfaces, it has
two centers of curvature. Since there are two centers of curvature, we may represent
them as C 1 and C 2. The distance of the optical centre from either of the centre of
curvatures is termed as the radius of curvature.
2. Principal axis
The straight line joining the two centers of curvature and the optical centre (O) is
called the principal axis of the lens.
3. Optical centre
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