Question

A student obtained a sharp image of a lighted candle using a convex lens. now he wants to focus a distant lamp on a far away electric pole. in which directions should, tha lens be move for this screen, to get a sharp image on the screen. justify your answer

Answer 1

Given:
A student obtains sharp image of candle on screen using convex lens.
To focus distant lamp , where  the  lens should be placed?
The lens should be moved towards screen so that a clear image and sharp image is obtained.
Reason:
When we move lens towards screen, then object moves farther away from lens. Hence we can consider object at infinity , light rays from infinity incident on convex lens, after refraction converge at focus and image is formed there.

Answer 2

Answer:

towards the screen to obtain clear image