Why does a coin placed at the bottom of a water-filled bowl appear to be at a shallower depth than it actually is?
Generated by claude-sonnet-4-6 · 2026-06-26 01:12 · grounding rag
Model Answer
When light rays travel from water (denser medium) to air (rarer medium), they bend away from the normal at the surface. The refracted rays, when extended backwards, appear to meet at a point higher than the actual position of the coin. This is refraction of light, which makes the coin appear raised/shallower than its real depth.
Source: Chapter 9, Section 9.3 Refraction of Light
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Explanation
- The key concept is refraction — light bends when passing from one medium to another.
- Specifically state the direction: denser → rarer medium → bends away from normal.
- Mention that the apparent position is higher than the actual position because the eye traces refracted rays backward in a straight line.
- Examiners look for: (1) naming refraction, (2) explaining the bending direction/apparent shift. Both points earn the 2 marks.