A concave mirrorr of focal length `f_(1)` is placed at a distance of `d` from a convex lens o
Channel: Doubtnut
Date: 2020-01-19

A concave mirrorr of focal length `f_(1)` is placed at a distance of `d` from a convex lens of focal length `f_(2)`. A beam of light coming from infinity and falling on this convex lens-concave mirrorr combination returns to infinity. The distance `d` must equal.