Question

An equiconvex lens having $\mu=1.5$ and radius of curvature $10\, cm$ is cut into four equal parts as shown in the diagram.

Now two parts are used to form the image as shown in the diagram

Now considering $O$ as origin $(0,0)$, if $x$ and $y$ co-ordinate of image is $(n \,cm , m \,cm )$, then the value of $(n \times m)$ is

Answer 1

Now lens $1$ and lens $2$ have $f=20 \,cm$.

Now for lens $2$ , principal axis is $2 \,mm$ above the given axis, so image is at focus point

$n=40 \,cm ; m=0.2 \,cm$
so, $n m=8$