A concave mirror forms a real image, on a screen of thrice the linear dimension of a real
Channel: Doubtnut
Date: 2020-02-20

A concave mirror forms a real image, on a screen of thrice the linear dimension of a real object placed on its principal axis. The mirror is moved by 10 cm along its principal axis and once again a sharp image of the object is obtained on the screen. This time the image is twice as large as the object. Find the focal length of the mirror.