CAIE IGCSE Physics Total Internal Reflection
Practise stating the two conditions for total internal reflection and trace rays through water, glass or an optical fibre with correct incidence geometry.
- Syllabus
- 2026–2028
- Course
- Physics 0625
Exam points
- require light to travel from the optically denser medium toward the less dense medium
- compare the incidence angle with the critical angle and require i > c for total reflection
- trace repeated equal-angle internal reflections until the ray exits an optical fibre
3.2.2.5—Internal reflection and total internal question 1
Fig. 5.1 shows four rays of red light, P, Q, R and S, coming from a spotlight in a swimming pool.
Fig. 5.1
Explain why ray S is totally internally reflected at the water surface.
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