Question

Which the following statements is true?(A) aconvex lens has 4 dioptre power having a focal length 0.25m(B) aconvex lens has -4Dioptre power having a focal length 0.25m(C) A concave lens has 4 dioptre power having a focal length 0.25m(D) a concave lens has -4 dioptre power having a focal length 0.25m

Answer 1

1. a convex lens has 4 dioptre power having a focal length 0.25 metre

Explanation:

the focal length of a convex lens is always positive