Question

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

Answer 1

u =infinity

v= -80 cm

1/v-1/u =1/f

1/infinity - 1/-80

0-1/-80 = 1/80

1/80 =1/f

f = 80cm

P=1/f = 1.25 m

P= 1.25 D

Concave lens is used to correct this defect and concave is a diveeging lens.

Answer 2

Explanation:

To correct the myopia the person concerned should use concave lens of focal length (f) = -80 cm = -0.80 m

Power of lens (P) = 1/f(m) = 1/-0.80 = 100/-80 = -1.25 D.