A person can see objects between 35cm to 400 cm. What defect is he suffering from? give a correction for this defect.

Asked by  | 13th Mar, 2013, 12:52: AM

Expert Answer:

Since the person is not able to see farther than 400 cm, he is suffering from myopia. Hence, a concave lens of suitable power is required to correct his defect. The focal length of the lens is given by his far point i.e.,

Focal length =  Far point

400 cm

? Power of the lens = -(1/f) = -100/400 = -.25 D

Hence, a concave lens of power .25 D is required to correct the given defect of vision.

Answered by  | 13th Mar, 2013, 03:53: PM

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