Draw a ray diagram to show the correction of eye defect of an old man who can not see an object placed closer than 1 m from his eye, clearly.
Generated by claude-sonnet-4-6 · 2026-06-15 06:51 · grounding rag
Model Answer
The old man cannot see objects closer than 1 m — his near point has receded. This is Presbyopia (or Hypermetropia). It is corrected by a convex (converging) lens.
Ray Diagram:
```
Object Convex Lens Eye
| | |
O ---rays----[( )]---------→ Retina
(lens refracts (image
rays to formed
converge) here)
```
The convex lens converges the rays from the nearby object so that they appear to come from a point farther away (≥ 1 m), allowing the eye to focus them on the retina.
Source: Chapter 10, Section 10.2 – Defects of Vision and their Correction
---
Explanation
- The examiner expects you to identify the defect (Presbyopia/Hypermetropia) and name the corrective lens (convex lens) — 1 mark.
- A clear, labelled ray diagram showing the convex lens bending rays so the image falls on the retina — 1 mark.
- Key point: the lens virtually shifts the near object to the person's near point (1 m here), making it visible. Mention this briefly.
- Since diagrams are hard to draw in text, in the actual exam draw a proper eye diagram with the convex lens in front, showing diverging rays being converged onto the retina.