Physics · Ch 6 — Optics
Image Formation in Spherical Mirrors
Image Formation in Spherical Mirrors
The image formed by a spherical mirror can be located graphically using any two of four standard construction rays, drawn from a point on the object: (i) a ray parallel to the principal axis reflects through (concave) or appears to come from (convex) the principal focus ; (ii) a ray travelling through (concave) or directed towards (convex) the focus reflects parallel to the principal axis, the reverse of rule (i); (iii) a ray travelling through the centre of curvature strikes the mirror normally (since every normal passes through ) and retraces its own path back through after reflection; (iv) a ray striking the pole reflects symmetrically about the principal axis, obeying the ordinary law of reflection with the axis itself acting locally as the normal at . The intersec …
What this figure shows. Four separate small diagrams, each tracing one of the standard rays from a point on an object AB reflecting off a mirror with pole P, focus F and centre of curvature C. (a) A ray parallel to the axis reflects through the focus. (b) A ray travelling through the focus reflects parallel to the axis (the reverse of rule a). (c) A ray aimed at the centre of curvature strikes the mirror normally and retraces its own path back through C. (d) A ray striking the pole itself reflects symmetrically about the axis, obeying the ordinary law of reflection there. Any two of these four rays, drawn from the same object …