Question

A person can see only the objects placed between $1.2m$ and $5m$. Explain this defect and what is the nature and power of lens used to correct this defect ?

Answer 1

There are some possible reasons due to this defect of vision may have arisen.

$a)$ elongation of the eyeball

$b)$ excessive curvature of the lens.

the person is unable to see distinctly the objects placed beyond 5m from

his eyes because he is suffering from myopia.A myopic eye cannot see the

nearby objects clearly.

a convex lens of suitable focal length is used to restore proper vision.

After using a convex image is formed the retina.While before it, an image was

formed near the retina.

Focal length of convex lens is positive

$f=+5m$

$power=\frac{1}{f}=+\frac{1}{5}=+0.2D$