Some wireless doorbells use radio waves, whereas some home entertainment systems use infrared remote controls. Explain why a radio wave doorbell transmitter can signal the receiver through a solid brick wall, but an infrared remote control cannot operate a device if a solid brick wall is between them.
25 exam-style questions on Edexcel GCSE Physics 5.4 Uses and dangers of EM radiation. Each one has a worked solution and a mark scheme showing where the marks go.