Question

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?

Answer 1

A) she is suffering from myopia(short sightedness) since power is in negative. B)P=1/F where F=Focal length in metre And P= Power in Dioptre F = 1/-4.5 = - 22.22 cm C) Concavenature of the corrective lens are used.