Question

Optical axis of a thin equi-convex lens is the $x$-axis. The co-ordinates of a point object and its image are $(10 \,cm$, $1 \,cm )$ and $(100 \,cm ,-2 \,cm )$, respectively.

Answer 1

Let the position of, lens be $x$.
$\therefore u=-(x-10), v=+(100-x) $
$h_{1}=-2 \,cm , h_{o}=1 \,cm $
$\frac{v}{u}=\frac{h_{I}}{h_{0}}$
On solving, $x=40 \,cm$