Question

Optician has prescribed corrective lens indicating-0.4D.This means the lens prescribed is convex?True or false​

Answer 1

TRUE IS THE RIGHT ANSWER.......

Answer 2

False

Power of convex lens is positive and that of a concave lens is negative.

hence if power is negative this means focal length is negative and we have a diverging lens.

so the prescribed corrective lens is concave lens.