Read the following passage and answer the following questions from Q.1. to Q.4.
A student focuses the image of a candle flame, placed at about 2 m from a convex lens of focal length 10 cm, on a screen. After that he moves gradually the flame towards the Jens and each time focuses its image on the screen.
ln which direction does he move the lens to focus the flame on the screen ?

Options

A. away from screen
B. towards the screen
C. should not move the screen
D. toward the candle

Answer

D

Explanation

Let us assume the screen to lens distance is greater than 20 cm. Since it is required to get image beyond 2F the object should be F and 2F on other side of the lens. Hence student will move the lens towards candle. (F means a location at a distance from lens that equals the focal length of lens. 2F means distance that equals twice the focal length).