A technician measures the speed of light and the critical angle for three transparent materials.
| Material | Speed of light in the material (108 m/s10^8\ \mathrm{m/s}108 m/s) | Critical angle (∘^\circ∘) |
|---|---|---|
| P | 1.8 | 37 |
| Q | 2.0 | 42 |
| R | 2.2 | 47 |
State how the critical angle changes as the speed of light in the material increases.
93 exam-style questions on Edexcel GCSE Physics 5.1 Reflection, refraction and lenses, covering 5.1.1 Reflection, refraction and total internal reflection, 5.1.2 Specular and diffuse reflection, 5.1.3 Colour of light: absorption and filters, 5.1.4 Lenses: power, focal length and shape, 5.1.5 Ray diagrams for converging and diverging lenses, and 5.1.6 Real and virtual images. Each one has a worked solution and a mark scheme showing where the marks go.