Question

A doctor has prescribed a correctly lens of power -1.2 D to a person suffering from a defect of vision identify the defect of vision and the type of 0lens to be used find the focal length of the lens

Answer 1

Explanation:

Defect of vision is Myopia or Near-sightedness.

Concave lens should be used.

Given- Power, P = -1.2D

Since, P= 1

f (in metres)

Therefore, -1.2 = 1

f

f = 1

-1.2

f = - 1×10 f = - 5

12 6

f = - 0.84m (approx.)