In an experiment a convex lens of focal length 15 cm is placed coaxially on an…
PHYSICS · Single correct · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments
Problem
In an experiment a convex lens of focal length 15 cm is placed coaxially on an optical bench in front of a convex mirror at a distance of 5 cm from it. It is found that an object and its image coincide, if the object is placed at a distance of 20 cm from the lens. The focal length of the convex mirror is:
(1) 27.5 cm
(2) 20.0 cm
(3) 25.0 cm
(4) 30.5 cm