Question

Power of Lens.
Plz answer this question

Answer 1

• The power of a lens is defined as the reciprocal of the focal length. Lens power is measured in dioptres (D). Converging (convex ) lenses have positive focal lengths, so they also have positive power values. Diverging (concave ) lenses have negative focal lengths, so they also have negative power values.

Answer 2

Its denoted by D-Diopter. Its unit is m-1.The power of lens obtained from its focal length (f). D=1/f. The power of lens is defined as the reciprocal of its focal lenght.