A beam of light converges to a point `P`. A lens is placed in the path of the covergent beam
Channel: Doubtnut
Date: 2020-08-02

A beam of light converges to a point `P`. A lens is placed in the path of the covergent beam `12 cm` from `P`. At what point does the beam converge if the lens is  (a) a convex lens of focal length `20 cm`  (b) a concave lens of focal length `16 cm` ?