Question

(i) Explain with the help of labelled ray diagram, the defect of hypermetropia. How is it corrected by a lens?

Hint:

For hypermetropia, convex lenses are used to converge the light rays before they enter the eye, ensuring that the image is focused on the retina.

Answer 1

Hypermetropia:
Hypermetropia, also known as farsightedness, is a vision defect in which the image of a nearby object is formed behind the retina. This occurs when the eyeball is too short or the eye lens is too weak. In such cases, the person is unable to focus on nearby objects clearly, but distant objects can be seen clearly.
Ray Diagram for Hypermetropia:
In the diagram below, the rays from a near object (O) are converging behind the retina, forming an image beyond the focal point. The defect is corrected by using a converging lens (convex lens), which helps to focus the rays on the retina by converging them before they enter the eye.
\includegraphics[width=0.5\linewidth]{image87.png} Correction:
Hypermetropia is corrected using a convex lens (converging lens) that helps focus the image on the retina. The convex lens converges the incoming rays so that the image is formed directly on the retina, allowing the person to see near objects clearly.