A card sheet divided into squares each of size $1\; mm^2$ is being viewed at a distance of 9 cm through a magnifying glass (a converging lens of focal length 10 cm) held close to the eye. At what distance should the lens be held from the card sheet in order to view the squares distinct with the minimum possible magnifying power ? What is the magnification in this car ?

Question

$\begin{array}{1 1} 3.0 \\ 2.5 \\ 3.5 \\ 2.0 \end{array} $