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The distance between object and its two times magnified real image as produced by a convex lens is 45 cm. The focal length of the lens used is ______ cm.

Asked in JEE Main 30th Jan 1st Shift 2024 · Lens formula and magnification

Answer: 10

Step-by-step solution

Real image on the other side: v = 2|u| and |u| + v = 45.

|u| = 15 cm, v = 30 cm.

1/f = 1/(30) + 1/(15) = 1/(10)

f = 10 cm

→ 10

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