Question

Figure 5.6 shows a point source of light S, a convex lens L and a plane mirror M. The three are placed such that rays of light from S return to it after reflection from M.

(a) What is the distance OS called?
(b) To which point (left of S, on S, or right of S) will the rays return if M is moved to the left and brought in contact with L?
[2 MARKS]

Answer 1

Each subpart: 1 Mark each

(a) It is called focal length of the lens.
(b) Rays will return to point S.