A student investigates the reflection of light using a plane mirror and pins on a ray-trace sheet.
The student draws an incident ray line and places two pins, P1P_1P1 and P2P_2P2, along it. State the minimum recommended distance between P1P_1P1 and P2P_2P2 and explain why this distance is necessary for an accurate ray-trace.
The student sets the angle of incidence to i=55∘i = 55^\circi=55∘. (i) Calculate the expected angle, θ\thetaθ, between the incident ray and the reflecting surface of the mirror. (ii) State the expected angle of reflection, rrr.
Suggest two practical precautions that the student should take when performing this ray-trace experiment to ensure the accuracy of their drawings and alignments.
Suggest one practical reason why the measured angle of reflection might not perfectly match the theoretical prediction from the law of reflection, even when the experiment is performed carefully.
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.