A concave mirror of focal length 20 cm is placed as shown in

Last updated: 6/30/2023

A concave mirror of focal length 20 cm is placed as shown in figure A circular disc of diameter 2 cm is placed on principal axis of mirror with its plane perpendicular to the principal axis at a distance 30 cm from the pole of mirror The radius of disc is increasing according to r 1 2t cm s then rate at which radius of image is changing Select an answer A B C 20 cm D 2 cm s increasing 4 cm s increasing 2 cm s decreasing 4 cm s decreasing