We wish to obtain an equal sized inverted image of a candle flame on a screen kept at a distance of 4 m from the candle flame.
(a) Name the type of lens that should be used.
(b) what should be the focal length of the lens and at what distance from the candle flame the lens be placed ?
(c) Draw a labelled diagram to show the image formation in this case.

Explanation

(a) Convex lens
(b) Focal length of the lens should be 2 m. Distance of candle flame from the lens is 4 m.