Question

A object is placed at $1cm$ in front of a concave mirror of focal length $10cm$. Find image position.

• A. $1.11cm$
• B. $10cm$
• C. $1cm$
• D. $0cm$

Answer 1

The correct option is A $1.11cm$

Given:

$f=-10,u=-1$

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

$\frac{1}{v}+\frac{1}{-1}=\frac{1}{-10}$
$\frac{1}{v}=\frac{1}{-10}+1$
$=\frac{-1+10}{10}=\frac{-9}{10}$
Therefore, image distance, $v=\frac{-10}{9}=1.11cm$