Describe the role of the following components in the stated applications: (a) radio waves – radio and television communications, astronomy (b) microwaves – satellite television, mobile (cell) phone, Bluetooth, microwave ovens (c) infrared – household electrical appliances, remote controllers, intruder alarms, thermal imaging, optical fibres (d) visible light – photography, vision (e) ultraviolet – security marking, detecting counterfeit bank notes, sterilising water (f) X-rays – hospital use in medical imaging, security scanners, killing cancerous cells, engineering applications such as detecting cracks in metal (g) gamma rays – medical treatment in detecting and killing cancerous cells, sterilising food and medical equipment, engineering applications such as detecting cracks in metal

Know that for a transverse wave, the direction of vibration is at right angles to the direction of the energy transfer, and give examples such as electromagnetic radiation, waves on the surface of water, and seismic S-waves (secondary)