An equiconvex lens of power P is cut into two identical halves by a plane perpendicular to its principal axis. The power of one of the resulting halves will be

Step-by-step solution

For an equiconvex lens, the power is given by Lens Maker's formula as P = ( - 1) ( 1 R - (- 1 R ) ) = 2( - 1) R . When the lens is cut by a plane perpendicular to the principal axis, each half becomes a plano-convex lens. The radii of curvature for one of these halves are R and . The power of this new plano-convex lens is P' = ( - 1) ( 1 R - 1 ) = - 1 R . Comparing the two expressions, we get P' = P 2 . Answer: P 2