Question

How are power and focal length of a lens related? Express in terms of formula. ​

Answer 1

Explanation:

A powerful converging lens will focus parallel light rays closer to itself and will have a smaller focal length than a weak lens. The power of a lens is given by the equation P=1f P = 1 f .

Answer 2

Explanation:

A powerful converging lens will focus parallel light rays closer to itself and will have a smaller focal length than a weak lens. The power of a lens is given by the equation P=1f P = 1 f .

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.

• A lens with a focal length of two meters has a power of one-half diopter because the reciprocal

of two is one-half or D = 1/2f