Question

If focal length of a convex lens is 20 cm at what is the power of the lens?

Answer 1

Given: Focal length (f ) = 20 cm = 0.2 m

To find: Power of the lens (P)

Formula: P = `1/("f"("m"))`

Calculation: From formula, P = `1/0.2` = 5 D

The power of the convex lens is 5 D.