Question

Why is normal eye not able to see clearly objects placed closer than 25 cm?

{AT LEAST 50 WORDS}

Answer 1

Due to accommodation property of the lens, normal eye can focus objects clearly when placed between 25 cm and infinity. But objects placed at a distance less than 25cm , the ciliary muscles could not bulge eye lens more. Hence the object appears blurred to the eye.

Answer 2

The lens (convex lens) of the eye is made up of a fibrous, jelly like material & it is held in position by ciliary muscles. Its focal length is not fixed but changes to see objects placed at distant and closer by contraction and relaxation of ciliary muscles. To see closer objects the focal length of lens is decreased by ciliary muscles. However it is possible to some extent that is 25 cm from the eye. The near point at the closest distance, at which objects can be seen clearly is called Near Point.

This is the reason why a normal eye not able to see the objects clearly placed closer than 25cm.