# A person is not able to read from a book until he keeps it at 50 cm. Determine the power of corrective lens.

2
by shivjot

2015-02-25T19:08:34+05:30

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Since the person is able to read clearly from a distance of 50 cm,
focal length required = 50 cm = 0.5m

Power =

Power of corrective lens is 2D.
U r missing that which lens is this actually and u have to explain what type of defect he is suffering from , u have to explain the questioner all the concepts of this problem
Only the power was asked. And I answered that.
2015-02-25T19:33:09+05:30
The corrective lens should have focal length 50 cm = 0.5 m.
Thus, power of lens = 1/0.5 = 2 D
The person is suffering from hypermetropia.
In hypermetropia, the near point of the eye shifts from 25 cm to some greater distance.
A convex corrective lens is used to remedy this problem.
Is this lens concave or convex and from which defect is the person suffering from????