A convex lens of power and a concave lens of focal length are kept in contact

PHYSICS · Multi-part · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments

Problem

A convex lens of power

2\,\mathrm{D}

and a concave lens of focal length

40\,\mathrm{cm}

are kept in contact. Find: (a) Power of the combination. (b) Equivalent focal length.