Which statement is correct?
The speed of light in a medium is equal to the speed of light in a vacuum divided by the refractive index of the medium.
When a light ray passes from air into glass, the angle of refraction is always greater than the angle of incidence.
The sine of the critical angle at a medium-air interface is equal to the refractive index of the medium.
The angle of refraction is directly proportional to the angle of incidence when light passes from air into water.
216 exam-style questions on CIE IGCSE Physics 3.2 Light, covering 3.2.1a Reflection of light, 3.2.1b Images in a plane mirror, 3.2.2 Refraction of light, 3.2.2a Refraction of light, 3.2.2b Total internal reflection, 3.2.2c Refractive index and critical angle, 3.2.2d Optical fibres, 3.2.3a Converging and diverging lenses, 3.2.3b Ray diagrams and the nature of images, 3.2.3c Virtual images and the magnifying glass, 3.2.3d Correcting long-sightedness and short-sightedness, and 3.2.4 Dispersion of light. Each one has a worked solution and a mark scheme showing where the marks go.