A point object in air is in front of the curved surface of a plano-convex lens. The radius of curvature of the curved surface is 30 c m and the refractive index of the lens material is 1.5 , then the focal length of the lens (in cm) is ___________.

Question

A point object in air is in front of the curved surface of a plano-convex lens. The radius of curvature of the curved surface is 30 c m and the refractive index of the lens material is 1.5 , then the focal length of the lens (in cm) is ___________.,

MARKS App · Accepted Answer

1 f = μ - 1 1 R 1 - 1 R 2 R 1 = ∞ R 2 = - 30 c m 1 f = 1.5 - 1 1 ∞ - 1 - 30 1 f = 0.5 30 f = 60cm

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