Physics - Geometrical Optics Question with Solution | TestHub

Given, the near point of the person is $v=-50$ cm.

The object distance is $u=-25$ cm.

Using the lens formula:

$\frac{1}{f}=\frac{1}{v}-\frac{1}{u}$

$\frac{1}{f}=\frac{1}{-50}-\frac{1}{-25}$

$\frac{1}{f}=-\frac{1}{50}+\frac{1}{25}=\frac{1}{50}$ cm${}^{-1}$

$f=50$ cm $=0.5$ m

The power of the lens is given by:

$P=\frac{1}{f}=\frac{1}{0.5}=+2$ D

Answer: $2$ D