Question

Find the distance of the image when an object is placed on the principal axis at a distance of 10 cm in front of a concave mirror whose radius of curvature is 8 cm.

Answer 1

Given : $u=-10cm$ $R=-8cm=2f$ $f=-4cm$

To find : $v$

Solution: From mirror formula

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

$\frac{1}{v}-\frac{1}{10}=-\frac{1}{4}$

$\frac{1}{v}=\frac{-6}{10/4}$

$v=\frac{-20}{3}cm$