Define the following terms in the context of spherical mirrors : (a) Pole (b) Centre of curvature (c) Principal axis

Question

(i) Define the following terms in the context of spherical mirrors :
(a) Pole
(b) Centre of curvature
(c) Principal axis
(d) Principal focus
(ii) Draw ray diagrams to show the principal focus of a :
(a) Concave mirror
(b) Convex mirror
(iii) Consider the following diagram in which M is a mirror and P is an object and Q is its magnified image formed by the mirror.

state the type of the mirror M and one characteristic property of the image Q.

Answer 1

(i) (a) Pole : Centre of the reflecting surface of the mirror.
(b) Centre of curvature : The centre of the hollow sphere of which the reflecting surface of
mirror is a part.
(c) Principal axis : Straight-line passing through the pole and the centre of curvature of a spherical mirror.
(d) Principal focus : Incident rays parallel to principal axis, after reflection, either converge to or appear to diverge from a fixed point on the principal axis called principal focus of the spherical mirror.

(iii) Concave mirror  Image formed is virtual