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A thin plano convex lens made of glass of refractive index 1.5 is immersed in a liquid of refractive index 1.2. When the plane side of the lens is silver coated for complete reflection, the lens immersed in the liquid behaves like a concave mirror of focal length 0.2 m. The radius of curvature of the curved surface of the lens is : -

1. 0.15 m
2. 0.10 m
3. 0.20 m
4. 0.25 m

Correct answer: 0.10 m

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