Question

The far point of a myopic person is 100 cm in front of the eye. What is the nature and power of the lens required to correct the problem?

• A. Convex lens, Power = 1.5 D
• B. Concave lens, Power = -1.5 D
• C. Convex lens, Power = 1 D
• D. Concave lens, Power = -1 D

Answer 1

The correct option is D Concave lens, Power = -1 D

A myopic person can see things nearby clearly but cannot see things far. We need a lens which forms image at 100 cm for an object at infinity.

Using lens formula 1/f = 1/v -1/u
u = -∞
v = -100 cm
1/f = -1/100 cm
Power = - 100 cm = - 1 D
Negative focal length is a concave lens.