The power of lens is a measure of its ability to converge or diverge an incident beam of light.

It is defined as the reciprocal of the focal length, in meters .

The unit of power is m

^{-1}

^{}or dioptre.

**(also referred to as**

Optical power

Optical power

**dioptric power**,

**refractive power**,

**focusing power**, or

**convergence power**)

Sourse : http://en.wikipedia.org/wiki/Lens_power

Worked example :

Determine the power of each of the following lenses.

a) Convex lens, f = 10 cm,

b) Concave lens, f = 10 cm.

Solution :

a) power,P = 1/0.1

= 10 D

b) power , P = -1/0.1

= -10 D

## 0 comments:

## Post a Comment

Note: Only a member of this blog may post a comment.