Draw a ray diagram to show the refraction of a ray of light passing through an equilateral glass prism. Mark the angle through which the emergent ray bends from the direction of the incident ray and also name it.
Generated by claude-sonnet-4-6 · 2026-06-15 06:53 · grounding rag
Model Answer
Ray Diagram:
```
A
/\
/ \
/ \
P→ E →→→ F →S
/ \
B C
```
A ray PE is incident on face AB, refracts along EF inside the prism, and emerges as FS through face AC. The emergent ray FS bends towards the base of the prism compared to the original incident ray direction.
The angle between the incident ray (extended) and the emergent ray is called the angle of deviation (∠D).
(Diagram should show normals at E and F, angles ∠i, ∠r, ∠e, and ∠D marked clearly.)
Source: Chapter 10, Section 10.3 — Refraction of Light Through a Prism
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Explanation
- Examiners expect a labelled diagram showing: incident ray (PE), refracted ray (EF), emergent ray (FS), normals at both surfaces, and the angle of deviation ∠D marked between the extended incident ray and the emergent ray.
- The angle of deviation is the key term — must be named explicitly for full marks.
- The ray always bends towards the base of the prism; mentioning this can earn credit.
- Two marks: 1 for correct diagram with labels, 1 for naming the angle of deviation.