A persons right eye is corrected by a 30diopter lens worn 20

A person\'s right eye is corrected by a -3.0-diopter lens, worn 2.0 cm from the eye. (a) Is the person near or farsighted? (b) What is the person\'s far point without glasses?

Solution

Here,

power , P = -3 D

a) as the glasses used for correction is concave

the person is near sighted.

b)

focal length , f = 100/P cm

f = - 100/3 cm

f = -33.33 cm

let the persons far point is do

Using lens formula

1/f = 1/(di + 2) + 1/infinite

-1/33.33 = 1/(di + 2)

di + 2 = 33.33

di = -35.33 cm

the person\'s far point is 35.33 cm