Convex lens made up of glass μ g = 1.5 and radius of curvature R is dipped into the water. Its focal length will be (Refractive index of water = 4 3 )

Step-by-step solution

Here, μ g = 1.5 = 3 2 , μ w ᷿ = 4 3 R 1 = R , ⇒ R 2 = - R From, lens maker's formula 1 f = μ - 1 1 R 1 - 1 R 2 w h e r e μ = μ L μ M ∴ 1 f a ₐ = μ g μ a ₐ - 1 1 R - 1 - R ⇒ 1 f a = 1 R Also 1 f w ᷿ = μ g μ w ₐ - 1 1 R - 1 - R O r 1 f w = 1 4 R Or f w ᷿ = 4 R