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 immer

Question

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

TestHub · Accepted Answer

​ v 1.5 ​ = R 1.5 − 1.2 ​ v = 0.3 1.5 R ​ = 5 R f 1.2 ​ − 5 R 1.5 ​ = − R 1.2 − 1.5 ​ f 1.2 ​ = R 0.3 ​ × 2 ⇒ f = 2 R ⇒ R = 0.1 ​

Physics - Geometrical Optics Question with Solution | TestHub

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