Question

A doctor has prescribed a corrective lens of power +1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?

Answer 1

Power of lens $P = \frac 1f$
$P = 1.5\ D$
$f = \frac {1}{1.5}$

$f= \frac {10}{15}$
$f = 0.66\ m$
A convex lens has a positive focal length.

Hence, it is a convex lens or a converging lens.