Combined ScienceCode 5129
Electromagnetic spectrum
What this topic asks you to be able to do
- Know how the main regions of the electromagnetic spectrum are ordered by frequency and, separately, by wavelength
- Know that electromagnetic waves all share one speed: (a) in a vacuum it is 3.0 × 108 m/ s (b) in air it is approximately equal to the vacuum value
- Describe the role each of these regions plays in the applications given: (a) radio waves – communications by radio and television (b) microwaves – microwave ovens, Bluetooth and mobile (cell) phones (c) infrared – thermal imaging, remote controllers and household electrical appliances (d) visible light – vision and photography (e) ultraviolet – sterilising water and security marking (f) X-rays – medical imaging in hospitals, security scanners and killing cancerous cells (g) gamma rays – detecting and killing cancerous cells in medical treatment, sterilising medical equipment and food, and engineering uses such as detecting cracks in metal