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A farsighted person has a near point of ...

A farsighted person has a near point of 75 cm for one eye and a near point of 100 cm for the other .What pwers should corrective lenses have to allow the person to see an object clearly at a distance of 25cm.

Text Solution

Verified by Experts

(a) Distance of far point = x= 7.5 m = 750 cm
(a) Corrective lens is used 2 cm from the eye
So far point = x. = 750 - 2= 748 = 7.48m
Focal length of the lens = f = x.
f = - 7.48 m
Power of the corrective lens `=P=(1)/(f("in m"))`
`P=(1)/(-7.48)= -0.134D`
(b) If the contact lens were used then
f = - x= 7.5 m
then power of corrective lens = P
`=(1)/(f("in m"))= -0.133D`
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