The power of the lens is said to be one dioptre if its focal length is equal to 1 meter.
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.The diopter is the unit of measure for the refractive power of a lens. The power of a lens is defined as the reciprocal of its focal length in meters, or D = 1/f, where D is the power in diopters and f is the focal length in meters. Lens surface power can be found with the index of refraction and radius of curvature.
Power of a lens is the ability to converge or diverge the ray of light falling on it. ... A lens of small focal length has large power of converging or diverging a parallel beam of light. Unit of power is Diopter (D) Power of lens is 1 diopter if its focal length is 1 m. Consider 2 lenses with focal length.A 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.
The power of a lens is specified as P = 1F, where f is the focal length. The S.I. unit of power of a lens is m−1.