A student cannot see a chart hanging on a wall placed at a distance of 3 m from him. Name the defect of vision he is suffering from. How can it be corrected ? Draw ray diagrams for the (i) defect of vision and also (ii) for its correction.

1. Name of the Defect

The student is suffering from Myopia (also known as near-sightedness).

Reasoning: A person with myopia can see nearby objects clearly but cannot see distant objects distinctly. Since the student cannot see a chart hanging on a wall at a distance of $3\text{ m}$ (which is a distant object compared to the normal near point of $25\text{ cm}$), their far point is less than infinity (specifically, less than $3\text{ m}$).

2. Correction of the Defect

This defect can be corrected by using a concave lens of suitable power.

How it works: A concave lens of appropriate focal length diverges the parallel rays of light coming from a distant object before they enter the eye. This causes the rays to appear as if they are originating from the far point of the myopic eye, enabling the eye lens to focus the image precisely on the retina.

3. Ray Diagrams