51 exam-style questions on OCR GCSE Physics 5.3 Wave interactions, covering 5.3.1 Wavelength and how substances affect waves, 5.3.2 Wave velocity in different substances, 5.3.3 Convex and concave lenses, 5.3.4 Ray diagrams for reflection and refraction, and 5.3.5 Colour, absorption and reflection. Each one has a worked solution and a mark scheme showing where the marks go.