Question

What is the unit of power of a lens ?
Define it .

Answer 1

Answer:

The unit of power of lens is Dioptre (D)

It is equal to the reciprocal of the focal length measured in 'm'

$d \: \: = \: \: \frac{1}{f}$

Answer 2

Answer:

Power of a lens is the reciprocal of its focal length.

Dioptre is the SI unit of power of lens.

One Dioptre is the power of a lens whose focal length is 1 metre.

1d=1m^-1

Convex lens has positive power while concave lens has negative power.

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