Question

A real image
of the size of an object is formed by a convex lens when the object is at a distance of 12 cm from it. Find the focal length of the lens.
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Answer 1

m = 12 u. ⇒ f = 7.2 cm. Hence, The focal length is 7.2 cm. The image formed is real (convex lens forms diminished real image.)

Answer 2

focal length of the lens is 6 cm

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