Question

A person with a myopic eye cannot see objects beyond 1.2 m directly. What should be the type of the corrective lens used? What would be its power?

Answer 1

Hey Friend,

Since the person suffers from Myopia, the corrective lens will be concave or diverging lens.

Given, that the person can't see objects beyond 1.2 m directly. 
So, in order to view the distances beyond 1.2 m, the focal length of the lens should be 1.2 m.

Power of lens = 1 /  focal length (in meter)
P = 1/(-1.2) 
P = -0.83 Diopter

Therefore the power of the lens should be - 0.83 D

Hope it helps!

Answer 2

HELLO DEAR,

to see a distant object we must be use

concave lens of -1.2m

i.e f = -(distance of far point )

we know the formula

the power of lens = 1/f

=> 1/(-1.2)

=> -0.83D

p = -0.83D

for correct this defect of vision,
he must use a concave lens. 

I HOPE ITS HELP YOU DEAR,
THANKS