Question

Define power of lens . Lenses of focal length 25 cm calculate power of lens

Answer 1

$\fcolorbox{blue}{violet}{Hello}$
$\bold{ \underline{Power}}$
The Power of a lens is a measure of the degree of convergence or divergence of light rays falling on it.
It can also be defined as the reciprocal of focal length in metre.

$\bold{p}$
$= \frac{1}{f}$

converting 25 cm into m
$= \frac{25}{100}$
$= \frac{1}{4}$
$= \frac{1}{ \frac{1}{4} }$

$= 4$
so power of the lens is +4 dioptre.
$\huge{ \boxed{Thanks}}$