Brainlag PlusWhy light can be trapped inside glass or water, the critical angle, and how optical fibres and endoscopes use it.
Which boards ask for this
- Edexcel (Physics 1PH0): Physics only. Explain reflection, refraction and total internal reflection with ray diagrams, including the critical angle.
- AQA (Physics 8463): fibre optic communication is listed as a use of visible light. The critical angle is not a separate statement, but it is the reason fibres work.
- OCR Gateway (Physics A J249): reflection and refraction are in P5. Check with your teacher whether your course asks for the critical angle by name.
None of the boards asks you to calculate a critical angle from an equation at GCSE, so in this lesson critical angles are always given.
The rest of this lesson and its 23 practice questions are in Plus.
Screen 1 of 6, free to read.
- 23 exam-style questions, marked as you go, each with a worked solution
- The Refraction simulation beside every question
- Anything you get wrong is saved to your flashcards