Rays, normals and boundaries
Rays, normals and boundaries

Visible light is an electromagnetic wave, and in ray diagrams we show its path with straight lines called rays. At a boundary, the key reference line is the normal, drawn at 90∘90^\circ90∘ to the surface.
Step-by-step lessons covering Edexcel GCSE Physics Reflection, refraction and lenses for Foundation and Higher tier. Each lesson works through exam-style questions in Paper 1 and Paper 2 format. Master the required practical work and core equations early, since both papers can draw on content and maths skills from across the whole specification.