Refractive index of a glass convex lens is 1.5 . The radius of curvature of each of the two surfaces of the lens is 20 cm . The ratio of the power of the lens when immersed in a liquid of refractive i

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Refractive index of a glass convex lens is 1.5 . The radius of curvature of each of the two surfaces of the lens is 20 cm . The ratio of the power of the lens when immersed in a liquid of refractive index 1.25 to that when placed in air is

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Given data: μ g ​ = 1.5 , R 1 ​ = R 2 ​ = 20 cm , μ l ​ = 1.25 P 1 ​ = ( μ a ​ μ g ​ ​ − 1 ) ( R 1 ​ 1 ​ − R 2 ​ 1 ​ ) ∴ P 2 ​ = ( μ l ​ μ g ​ ​ − 1 ) ( R 1 ​ 1 ​ − R 2 ​ 1 ​ ) ​ = ( 1.5 − 1 ) ( R 1 ​ 1 ​ − R 2 ​ 1 ​ ) = ( 1.25 1.5 ​ − 1 ) ( R 1 ​ 1 ​ − R 2 ​ 1 ​ ) = ( 1.2 − 1 ) ( R 1 ​ 1 ​ − R 2 ​ 1 ​ ) ​ Taking ratio, P 1 ​ P 2 ​ ​ = 1.5 − 1 1.2 − 1 ​ = 5 2 ​

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