Question

the magnifying power of a magnifying glass is 6, the power of the lens (Ans = 20 diopter) need explanation​

Answer 1

Given:

$\sf{m = 6 \:}$ (magnification of magnifying glass)

$\sf{D \:= \:25\:cm}$  (Least distance of distinct vision.)

Answer:

The magnification of  magnifying glass,

$\sf{m \:= \:} {1 \:+ \:} {\dfrac{D}{f}}$

$\sf{6 \:= \:} {1 \:+ \:} {\dfrac{25}{f}}$

$\sf{5 \:= \:} {\dfrac{25}{f}}$

$\sf{f \:= \:} {\dfrac{25}{5}}$

$\sf{f \:= \: 5cm}$

$\sf{Power \:of \:Lens \:= \:}{\dfrac{100}{5}}$

$\sf{Power \:of \:Lens \:= \:20 \: Diopter}$