The radius of curvature of the face of planoconvex lens is 12 ~cm and its refractive index is 1.5. Then, the focal length of the lens is

Step-by-step solution

Given, refractive index of lens, =1.5 Radius of curved face, R₁=12 ~cm Radius of plane face, R₂= Now, using the expression of focal length, 1 f =( -1) [ 1 R₁ - 1 R₂ ] Substituting the values, we get aligned 1 f & =(1.5-1) [ 1 12 - 1 ] 1 f & =0.5 1 12 f & = 12 0.5 ~cm =24 ~cm aligned Hence, the focal length of given plano-convex lens is 24 ~cm .