Question :The far point of a myopic person is 80cm in front of the eye. What is the nature and power of the lens required to correct the problem.

Question :The far point of a myopic person is 80cm in front of the eye

1.	Question :The far point of a myopic person is 80cm in front of the eye. What is the nature and power of the lens required to correct the problem.
Answer» <P> Solution :The PERSON is suffering from an eye defect called myopia. In this defect, the IMAGE is formed in front of the retina. Hence a concave lens is used to CORRECT this defect of vission. OBJECT distance, u - infinity - `oo` Image distance, v=-8cm, Focal length=f According to the lens formula `1/v-1/u = 1/f` `- 1/80 - 1/oo = 1/f` `1/f =- 1/80` `f =- 80 cm = - 0.8 m` We know , power , P = 1/f(in meter) `P= (1)/(-0.8) = - 1.25D` A concave lens of power -1.25D is required by the person to correct his defect .