Question

A student obtained on a screen the sharp image of a candle flame placed at the farther end of laboratory table using a concave mirror. For getting better value of focal length of the mirror, the teacher suggested to him to focus the sun. What should the student do?
(A) Should move the mirror away from the screen.
(B) Should move the mirror towards the screen.
(C) Should move the mirror and screen both towards the sun.
(D) Should move only the screen towards the sun.

Answer 1

Initially, the screen was placed beyond the focus to capture the image of the candle flame placed at a finite distance from the mirror. So, in order to capture a bright image of the Sun (at infinity) on the screen, the student should move the mirror towards the screen.

Hence, the correct option is B.