State two advantages of transmitting signals using light pulses in optical fibres rather than electrical signals in copper cables.
An optical fibre has a glass core with a refractive index of 1.55. Calculate the critical angle c c\,c at the boundary between this glass core and the surrounding air.
State the meaning of the term critical angle.
A ray of light travelling inside the glass core strikes the boundary at an angle of incidence of 45∘45^\circ45∘. Explain what happens to this ray.
100 exam-style questions on CIE IGCSE Physics 3.2.2 Refraction of light. Each one has a worked solution and a mark scheme showing where the marks go.