Question

The shiny outer surface of a hollow sphere of aluminium of radius 50 cm is to be used as a mirror:

(a) What will be the focal length of this mirror?
(b) Which type of spherical mirror will it provide?
(c) State whether this spherical mirror will diverge or converge light rays.

Answer 1

(a) The radius of curvature of the mirror 'R' is 50 cm.

Therefore, focal length 'f' = $\frac{\mathrm{R}}{2}$ = 25 cm

(b) Since the outer surface is shiny, it will form a convex mirror.

(c) This spherical mirror will diverge the light rays.