A student is investigating the reflection of light by a plane mirror using a standard ray-tracing method. They draw a line representing the mirror surface and insert pins to track the incident and reflected rays.
State the minimum recommended distance between two tracking pins (P1P_1P1 and P2P_2P2) placed along an incident ray, and explain the physical reason for keeping these pins far apart.
The student wishes to investigate the relationship between the angle of incidence iii and the angle of reflection rrr. To obtain a reliable conclusion, they need to select a suitable range of angles. Suggest a series of five suitable values for the angle of incidence iii that they could use.
Describe two experimental precautions that should be taken during this ray-tracing experiment to ensure that results are as accurate as possible.
Explain one practical reason why the measured angle of reflection might not exactly equal the theoretically predicted angle of reflection, even when the experiment is carried out 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.