Question

A point object is placed an distance of $30cm$ from a convex mirror of focal length $30cm$. The image will form at :

• A. Infinity
• B. Pole
• C. Focus
• D. $15cm$ behind the mirror

Answer 1

The correct option is D $15cm$ behind the mirror

Given, $u=-30cm,f=30cm$
To find: $v$

Solution: From mirror formula

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

$\frac{1}{v}-\frac{1}{30}=\frac{1}{30}$

$\frac{1}{v}=\frac{2}{30}$

$v=15cm$

Hence image is formed behind the mirror.