Which of the following lenses would you prefer to use while reading small letters found in a dictionary?

Copy the given figure and complete it to show the formation of the image of the object $AB$. Name the lens used in the figure.

What is the $SI$ unit of the power of a lens?

The figure below shows a point source of light $S$,a convex lens $L$,and a plane mirror $M$. The three are placed such that rays of light from $S$ return to it after reflection from $M$. $(i)$ What is the distance $OS$ called? $(ii)$ To which point (left of $S$,on $S$,or right of $S$) will the rays return if $M$ is moved to the left and brought in contact with $L$?

When an object is placed at $2F$ in front of a convex lens,where will its image be formed?

$A$ concave lens made of a material of refractive index $n_{1}$ is kept in a medium of refractive index $n_{2}$. $A$ parallel beam of light is incident on the lens. Complete the path of rays of light emerging from the concave lens if
$(i)$ $n_{1} > n_{2}$ $(ii)$ $n_{1}=n_{2}$ $(iii)$ $n_{1} < n_{2}$