At what position a candle of length 3 cm be placed in front of a convex lens so that its - Physics - Radioactivity

Question

At what position a candle of length 3 cm be placed in front of a
convex lens so that its image of length 6 cm be obtained on a
screen placed at distance 30 cm behind the lens ?

Nidhi · Answer

Answer is 15cm
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At what position a candle of length 3 cm be placed in front of a convex lens so that its image of length 6 cm be obtained on a screen placed at distance 30 cm behind the lens ?