Study the following situations carefully and answer the questions that follow. A spherical mirror produces an image$48\mathit{ cm}$, in front it, when an object is positioned $12\mathit{ cm}$ from its pole. Calculate the focal length of the mirror.

The focal length of the mirror is$\frac{48}{5}\mathit{ cm}$. 
given u = 12 cm
          v = 48 cm
By using the mirror formula, we can find out the focal length of the mirror. 
$\frac{1}{f}=\frac{1}{v}+\frac{1}{u}$ , 
Where $v$ is the image distance, $u$ is the object distance, $f$ is the focal length.
Substituting values in the above formula we get,
$\Rightarrow \frac{1}{f}=\frac{1}{12}+\frac{1}{48}$ $\frac{1}{f}=\frac{5}{48}\mathit{ cm}$ 

$\Rightarrow \mathrm{f}=\mathrm{ }\frac{48}{5} \mathrm{cm}.\mathrm{ }$