Question

Two lenses are placed on paper.how will you identify them without touching.

Answer 1

you just see from these lenses and u'll be able to identify the difference coz they r of different types so they will have different properties as well as tendency. The size will be different which will help us to get it.

Answer 2

if you see the lines of paper blur it is a convex lens and if the lines are seem to be clear it is a concave lens