Question

how will you distinguish between convex lens and concave lens without touching them​

Answer 1

Answer:

Convex Lens: It is thick in middle and thin at edges.

Concave Lens: It is thin in middle and thick at edges.

Explanation:

This is the main difference between them you can find without touching them.

Answer 2

Answer:

Convex lens will be thick in middle and concave lens will be thick at the centre.