A light bulb is placed at a distance of 8 cm from the concave mirror having a focal length of 5 cm. The distance of the image from the mirror is ____________.

Object's distance, u = -8 cm

Focal length, f = -5 cm

By, Mirror Formula, we have $\frac{1}{\mathrm{v}} = \frac{1}{\mathrm{f}} - \frac{1}{\mathrm{u}}$

$\frac{1}{\mathrm{v}} = \frac{1}{\mathrm{f}} - \frac{1}{\mathrm{u}}$
$\frac{1}{\mathrm{v}} = \frac{1}{(-5)} - \frac{1}{(-8)}$
$\frac{1}{\mathrm{v}} = \frac{-1}{5} + \frac{1}{8}$

$\frac{1}{\mathrm{v}} = \frac{-8+5}{40} =\frac{-3}{40}$
 Hence, $\mathrm{V} =-13.33 \mathrm{cm}$