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~~, OUTER SURFACE OF A POLISHED SPOON, SeiSASe crane, INNER SURFACE ACTS AS CONCAVE, , 1.07. IMPORTANT TERMS IN RESPECT OF SPHERICAL MIRRORS, , Th, e centre of a hollow sphere of which the curved, , Centre of curvature ;, is denoted by C as, , a., or spherical mirror forms a part is called centre of curvature. |, re. 1t, , , , , , , , A line drawn from the centre, , of curvature (C) to any point, on the surface of a spherical, Mirror is perpendicular to the, surface of the mirror., , shown in figure 9., The centre of curvature is not the, part of the spherical mi, mirror. The centre of, , curvature lies in front of a concave mirr, or and the centri :, e of curvature lies, , , , behind the convex mirror., , Reflecting. ~~~ i, surface , , , Convex mirror, , f, Concave mirror, FIGURE 9, 2. Radius of curvature : The radius of a hollow sphere of which the spherical mirror, forms a part is called radius of curvature. It is denoted by R (Figure 9). 6, , The radius of curvature is also not the part of the spherical mirror., 3. Pole : The mid point of a spherical mirror is called its pole. It is denoted by P, , , , , AL..., , (Figure 9)., , 4, Aperture : The diameter of the part of a spherical mirror exposed to the incident light oyecties, is called the aperture of the spherical mirror. The apertures of a concave mirror and @tinfinity (A), a convex mirror are represented by the diameter of XY as shown in figure 9., , al axis : A line joining the centre of curvature (C) and pole (P) of aspherical 8, , 5. Princip:, mirror and extended on either side is called principal axis., , SS . s 5 2, A point on the principal axis of a spherical mirror where the, axis meet or appear to meet after reflection from, , , , , 6. Principal focus :, rays of light parallel to the principal, d principal focus. It is denoted by F. Object lies, oe @, , the spherical mirror is calle:, In case of a concave mirror, the rayS of light parallel to the principal axis after., shown in figure 10 (A). So, principal soueiats, , reflection actually meet the principal axis a “F as, , focus of a concave mirror is real., In case of convex mirror, the rays of light parallel to the principal axis after reflection, F as shown in figure 10 (B). So,, , appear to meet (or diverge from) the principal axis at, principal focus ofa convex mirror is virtual.