This question is about how light travels through different media.
A ray of light is directed inside a semicircular glass block towards the center of its flat face, which is in contact with air.
Under certain conditions, the ray of light does not exit the glass block but is reflected entirely inside it. (i) State the name of this process. (ii) If the angle of incidence of this ray at the glass-air boundary is 50∘50^\circ50∘, state the angle of reflection.
The direction of the incident ray is now changed so that the light passes out of the glass block into the air. (i) Describe how the direction of the ray changes as it crosses the boundary from glass to air. (ii) State the name of this process.
(i) State the equation linking critical angle, ccc, and refractive index, nnn. (ii) The refractive index of the glass block is 1.521.521.52. Calculate the critical angle for the boundary between this glass and air. Give your answer to three significant figures. (iii) The light source is adjusted so that the ray of light meets the glass-air boundary at an angle of incidence of 40∘40^\circ40∘. Explain what happens to this ray of light.
30 exam-style questions on Edexcel IGCSE Physics Light and sound. Each one has a worked solution and a mark scheme showing where the marks go.