Question

Define one dioptre of power of Lens​

Answer 1

dioptre (British spelling) or diopter (American spelling) is a unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres. (1 dioptre = 1 m−1.) It is thus a unit of reciprocal length.

Answer 2

one dioptre is the power of a lens whose focal length is 1 metre