A student investigates the refraction of light through a rectangular transparent block using the pin-tracing method.
During the experiment, the student measures the angle of incidence i=35∘i = 35^\circi=35∘ and the corresponding emerging angle θ=38∘\theta = 38^\circθ=38∘.
State two precautions that the student should take when using pins to ensure that the ray-trace is as accurate as possible.
A second student suggests that iii should be equal to θ\thetaθ within the limits of experimental accuracy (defined here as ±4∘\pm 4^\circ±4∘). State whether the values of i=35∘i = 35^\circi=35∘ and θ=38∘\theta = 38^\circθ=38∘ support this suggestion. Justify your answer.
The student plans to test the hypothesis that i=θi = \thetai=θ for all possible angles of incidence. Describe briefly how they would test this suggestion. State the minimum number of additional values of iii that should be tested.
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.