Question

The above lens has a focal length of 14 cm. The object of height 4 mm is placed at a distance of 7 cm from the pole. Find the height of the image.​

Answer 1

Answer:

$h=4mm=0.4cm$

$u= -7cm$

$f=14cm$

$h'=?$

$\frac{1}{f}=\frac{1}{v}-\frac{1}{7}$

$\frac{1}{v}=\frac{1}{14}-\frac{1}{7}$

$\frac{1-2}{14}=\frac{-1}{14}$

$v=-14cm$

$m=-\frac{v}{u} =\frac{h'}{h}$

$m=\frac{-14}{-7}=\frac{h'}{0.4}$

∴$h'=0.8cm$