The focal length of a thin biconvex lens is `20 cm`. When an object is moved from a distance of
Channel: Doubtnut
Date: 02/08/2020

The focal length of a thin biconvex lens is `20 cm`. When an object is moved from a distance of `25 cm` in front of it to `50 cm`, the magni-fication of its image changes from `m_(25) to m_(50)`. The ratio `(m_(25))/(m_(50))` is.