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A thin convex lens made from crown glass       = μ 2 3 has focal length f. When it is measured in two different liquids having refractive indices 3 4 and 3 5 , it has the focal lengths f 1 and f 2 respectively. The correct relation between the focal lengths is -

1. f 1 > f and f 2 becomes negative
2. f 2 > f and f 1 becomes negative
3. f 1 and f 2 becomes negative
4. f 1 = f 2 < f

Correct answer: f 1 > f and f 2 becomes negative

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