A person can see objects clearly only when they lie between `50cm` and `400 cm` from his eyes. In order to increase the maximum distance of distinct vision to infinity, the type and power of the correcting lens, the person has to use, will be

Options

A. concave, `-0.2`diopter
B. convex, `+0.15` diopter
C. convex,`+2.25` diopter
D. concave, `-0.25`diopter

Answer

D

Explanation

As we want to correct myopia , so, far point must go to infinity.
`u=-4m, u=-oo,P=?`
`P=(1)/(f)=(1)/(v)-(1)/(u)=(1)/(-4)-(1)/(oo)=-0.25D`
`(-)` implies concave mirrorr