A convex lens of refractive index has two surfaces of equal radius of curvature R . The focal length of convex lens is

Step-by-step solution

Using the lens maker's formula: 1 f = ( - 1) ( 1 R₁ - 1 R₂ ) For a biconvex lens with equal radii of curvature, R₁ = +R and R₂ = -R . Substituting these values into the formula: 1 f = ( - 1) ( 1 R - 1 -R ) 1 f = ( - 1) ( 2 R ) f = R 2( - 1) Answer: R 2( - 1)