Question

An object is placed at a distance of $12\text{cm}$ from a convex mirror of radius of curvature $12\text{cm}$. Find the position of the image from mirror.

• A. $+4\text{cm}$
• B. $-4\text{cm}$
• C. $+6\text{cm}$
• D. $-6\text{cm}$

Answer 1

The correct option is A $+4\text{cm}$

Given:
Object distance, $u=-12\text{cm}$
Radius of curvature, $R=+12\text{cm}$
So, focal length, $f=\frac{+12}{2}=+6\text{cm}$

From mirror formula,

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

$\Rightarrow \frac{1}{v}+\frac{1}{(-12)}=\frac{1}{(+6)}$

$\Rightarrow \frac{1}{v}=\frac{1}{4}$

$\Rightarrow v=+4\text{cm}$