A symmetric double convex lens is divided into two equal halves by a plane containing the principal axis. If the original lens has a power of 4 D , the power of one of the divided parts will be

Step-by-step solution

The power of a lens is given by the lens maker's formula: P = 1 f = ( - 1) ( 1 R₁ - 1 R₂ ) When a symmetric double convex lens is cut into two equal halves by a plane containing the principal axis, the radii of curvature R₁ and R₂ of the refracting surfaces for each half remain exactly the same as those of the original lens. Since the radii of curvature and the refractive index of the material do not change, the focal length f of each half remains the same as that of the original lens. The only change is that the a