A person cannot see clearly objects at a distance less than 100 cm. The power of the spectacles required to see clearly objects at 25 cm is
Options

Question

A person cannot see clearly objects at a distance less than 100 cm. The power of the spectacles required to see clearly objects at 25 cm is

G1 Physics · Accepted Answer

Derived solution: Step 1: Use the thin-lens relation for the correcting lens and the eye defect: a convex lens corrects hypermetropia, a concave lens corrects myopia, and a cylindrical lens corrects astigmatism. Step 2: Substitute the values given in the question and apply the geometry/sign convention shown. Step 3: On simplification the result is + 3 D. Therefore the correct option is B.