Question

how to observe lenses ​

Answer 1

$\huge \underline \bold\red{Answer}$

A lens is a shaped piece of transparent glass or plastic that refracts light. When light is refracted it changes direction due to the change in density as it moves from air into glass or plastic. Lenses are used in cameras, telescopes, binoculars, microscopes and corrective glasses. A lens can be convex or concave.

$\huge \underline \bold \red{Thanks}$