Waves · 1 question type
Past paper frequency (2018 to 2024)
This topic accounts for approximately 14% of your exam marks.
Wave equation (v = fλ), transverse vs longitudinal and EM spectrum properties tested consistently.
| Band | Typical uses |
|---|---|
| Radio waves | Television and radio broadcasting; long-range two-way radio communication; air-traffic control |
| Microwaves | Mobile phone signals; Wi-Fi and Bluetooth; satellite communications and weather radar; heating food in a microwave oven |
| Infrared (IR) | Heating elements in toasters and grills; thermal-imaging cameras and night-vision goggles; television remote controls; short-range data links and optical fibres |
| Visible light | Sight; photography and video; visible-wavelength fibre-optic data transmission; lasers |
| Ultraviolet (UV) | Fluorescent strip lighting; security marks on banknotes that glow under UV; sterilising medical instruments and water supplies; producing vitamin D in skin |
| X-rays | Medical imaging of bones, teeth and dense tissues; airport security scanners; checking welds and pipework for cracks in industrial sites |
| Gamma rays | Sterilising surgical instruments and food without heating; treating cancer (radiotherapy); medical imaging using radioactive tracers (PET scans) |