Question

(i) What is myopia? state the two cause of myopia. With the help of labelled ray diagrams show
(a) the eye defect myopia
(b) correction of myopia using a lens.
(ii) Why is the normal eye unable to focus on an object placed within $10cm$ from the eye?

Answer 1

This is the defect of eyes in which the person has difficulty in seeing distant objects but can easily see nearby objects. This eye defect is also called as nearsightedness.

For the persons with Myopia, the far point is nearer than infinity. The image of the object placed at a distance is formed in front of the retina and not on the retina.

It is caused by:

1) Excessive curvature of the eye lens

2) Elongation of the eyeball

A myopic eye can be cured by using a concave lens of suitable power.

The ciliary muscles of our eyes are unable to contract after a certain point.

If the object is placed at a distance less than 10 cms from our eyes, then it will be reflected beyond the retina making it blurry for the viewer.

This happens because the light rays emitted are emitted to a point other than the focal point.