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A double convex thin lens made of the refractive index 1 . 6 has radii of curvature 15 cm each. What is the focal length (in cm ) of this lens when immersed in a fluid of refractive index 1 . 63 ?

Correct answer

-407.5

Step-by-step solution

Focal length of lens in given by 1 f w = μ g - 1 1 R 1 - 1 R 2 = 1.6 1.63 - 1 1 15 + 1 15 = - 0.03 × 2 1.63 × 15 = .0 6 1.63 × 15 s o , f w = - 815 2 = - 407.5 cm

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