Q18 of 30 Page 88

A person needs a lens of power –4.5 D for correction of her vision.

(a) What kind of defect in vision is she suffering from?


(b) What is the focal length of the corrective lens?


(c) What is the nature of the corrective lens?

(a) She is suffering from Myopia defect.


(b). Focal length is given by the reciprocal of power i.e.


Focal Length = 1/ Power of lens


Focal length = -100/4.5 cm


Focal length = -22.2 cm


(c) The corrective lens will be a concave lens.


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