Question

(a) Define the following terms in the context of spherical mirrors : (i) Pole
(ii) Centre of curvature
(iii) Radius of curvature
(iv) Principal axis
(b) Draw ray diagrams to show the principal focus of (i) a concave mirror, and (ii) a convex mirror.
(c) In the following diagram. MM' is a concave mirror and AB is an object. Draw on your answer-sheet a ray diagram to show the formation of image of this object.

Answer 1

Answer:

1 at focus

2 at the centre of curvature

Answer 2

Answer:

Explanation:

(a) Definitions:

1. Pole (P) is the central point of the reflecting surface of a spherical mirror.
2. Centre of curvature (C) is the centre of the sphere from which the spherical mirror is obtained.
3. Principal axis is the imaginary straight line passing through the pole and centre of curvature.
4. Principal focus (F) is the point on the principal axis of a spherical mirror where all the incident rays parallel to the principal axis converge or appear to diverge after reflection.

(b) Principal focus:

1. For a concave mirror, focus lies on the same side as the reflecting surface.
2. For a convex mirror, focus is obtained by extending the rays reflected from the surface of the mirror. The focus lies on the other side of the reflecting surface.

(c) M is a concave mirror. Image formed is virtual.