What is a simple microscope? Obtain the equation of magnification for the image formed at the near point (normal vision distance).

(N/A) simple microscope (or magnifying glass) is a converging lens of small focal length.
To use it,the object is placed at a distance less than or equal to the focal length $f$ of the lens. The eye is positioned close to the lens on the other side to view the erect,magnified,and virtual image.
Let the object be at distance $u$ and the image be at the near point $D$ (where $D \cong 25 \ cm$).
The linear magnification $m$ is given by:
$m = \frac{v}{u} \quad \dots (1)$
Using the lens formula:
$\frac{1}{f} = \frac{1}{v} - \frac{1}{u}$
Multiplying by $v$ on both sides:
$\frac{v}{f} = \frac{v}{v} - \frac{v}{u}$
$\frac{v}{f} = 1 - m$
$m = 1 - \frac{v}{f}$
Since the image is virtual and formed at the near point,we use sign convention $v = -D$:
$m = 1 - \frac{-D}{f}$
$m = 1 + \frac{D}{f}$