A student investigates the refraction of light through a transparent rectangular block. They draw an incident ray at an angle of incidence i=45∘i = 45^\circi=45∘ to the normal NLNLNL, and place two pins, P1P_1P1 and P2P_2P2, along this ray. After placing the block, they look through the opposite side and place two more pins, P3P_3P3 and P4P_4P4, so that they appear to align with the images of P1P_1P1 and P2P_2P2. They then draw the emergent ray JKJKJK through P3P_3P3 and P4P_4P4 and measure the angle θ\thetaθ between the emergent ray and the normal NLNLNL.
State two precautions that the student should take when placing the pins to ensure that the ray is traced as accurately as possible.
A student suggests that the angle of incidence iii should be equal to the emergent angle θ\thetaθ within the limits of experimental accuracy. For an angle of incidence i=45∘i = 45^\circi=45∘ and assuming a typical limit of experimental accuracy of ±3∘\pm 3^\circ±3∘, suggest a range of values for θ\thetaθ that would support the student's suggestion.
Describe briefly how a student could test the suggestion that i=θi = \thetai=θ for all possible values of iii in this experiment.
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.