This exam tips covers Exam Tips within Reflection & Refraction for GCSE Physics. Revise Reflection & Refraction in Waves for GCSE Physics with 15 exam-style questions and 15 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 12 of 13 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Topic position
Section 12 of 13
Practice
15 questions
Recall
15 flashcards
💡 Exam Tips
🎯 Common Question Types:
- Complete a ray diagram with correct angles (2–3 marks)
- Explain why refraction occurs at a boundary (3 marks)
- Describe/explain total internal reflection with a named application (4 marks)
- State and explain the difference between specular and diffuse reflection (2 marks)
📝 Key Command Words:
- State: Give the law of reflection as an equation (i = r)
- Describe: What happens to the light — direction, speed, wavelength
- Explain: Give the reason — speed change causes direction change
- Draw: Show normal, measure angles correctly, use arrows on rays
⚠️ Common Mistakes to Avoid:
- Measuring angles from the surface instead of the normal
- Forgetting to draw the normal in ray diagram questions
- Saying "light bends because it enters a denser medium" — it only bends if hitting at an angle
- For TIR: forgetting to state BOTH conditions (denser medium AND angle > critical)
Quick Check: Why does a diamond sparkle more than a piece of glass of the same shape?
Diamond has a higher refractive index than glass, which means a smaller critical angle (about 25° compared to 42° for glass). This means more light inside the diamond undergoes total internal reflection and is bounced around inside, producing more sparkle, rather than being transmitted out through the sides.