A ray of light traveling in air strikes the surface of a spherical glass marble of centre O O\,O at point AAA.
The refractive index of the glass is 1.50, and the angle of incidence at A A\,A is 45∘45^\circ45∘.
State the equation linking refractive index, angle of incidence, and angle of refraction when light enters a medium from air.
Show by calculation that the angle of refraction r r\,r at A A\,A is approximately 28∘28^\circ28∘.
The refracted ray travels through the glass marble and strikes the opposite inner surface at point BBB.
Explain, using the geometric properties of a circle, why the angle of incidence of the ray at B B\,B is also equal to rrr.
State the angle of reflection for the portion of the light that is reflected at BBB.
The remaining light is refracted as it emerges from the marble at B B\,B back into the air. Calculate the angle of refraction of this emerging ray.
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.