The power of a lens is + 1.5 D. Name the type of defects vision that can be corrected by using this lens. Find the focal length of the lens.

Power of a lens is = P = + 1.5 D.

Since power is positive hence the lens used is a convex lens.


Types of defects vision that can be corrected by using this lens Hypermetropia and presbyopia.


A person suffering from any of these defects is not able to see the nearby objects clearly.


The purpose of the convex lens is to increase the converging power of the lens and help to form the image of nearby objects on the retina.


Focal length = f


f = 1/P (in meters)


= 1/1.5 m


= 0.667 m


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