Question

If focal length of a convex lens is 80cm , what will be the power of the lens ?
(A) +1.5 diopter
(B) -1.5 diopter
(C) +1.25 diopter
(D) -1.25 diopter

Answer 1

$$\begin{gathered} P=\frac{1}{f\left(m\right)}=\frac{1}{0.8}=1.25D \\ optionC \end{gathered}$$