Question

Two different types of lens are placed on a set of newspapers. How will you identify them without touching

Answer 1

Two different types of lens simply means on will be concave and other will be convex so we can easily identify then by just looking at them ..the letters of the newspaper will appear slightly big through convex lens and slightly small through concave lens.

Answer 2

Convex lens magnifies a little more than the actual size of the letters, as it is placed right on the newspaper.  If the distance increases, then letters will appear even bigger. 

Concave lens will show the text even smaller than the actual size. This is because the diverging nature of the lens and the virtual image that is formed.

At home you could try this experiment with the spectacles of different types. You will observe the difference easily.