The electromagnetic spectrum

Parts of the electromagnetic spectrum

A large family of waves, each with a different wavelength range is called the electromagnetic spectrum (sometimes shortened to the EM spectrum). These waves all travel at the speed of light (300,000,000 metres per second) in a vacuum.

The table below lists the different radiations in the electromagnetic spectrum and shows some information about each radiation.

The electromagnetic spectrum
Type of waveTypical sourceExample of detectorApproximate wavelengthTypical usersDangers of over exposure
Radio: LWelectronic circuits, stars and spaceaerial and electronic circuit1kmcommunications, radio, TVsafe (unless very concentrated)
Radio: MWelectronic circuits, stars and spaceaerial and electronic circuit100mcommunications, radio, TVsafe (unless very concentrated)
Radio: VHFelectronic circuits, stars and spaceaerial and electronic circuit1mcommunications, radio, TVsafe (unless very concentrated)
Microwaveselectronic circuits, cool objectsaerial and electronic circuit1cm (10-2m)communications satellites, telephony, heating water and foodburning, if concentrated
Infra red (IR)electronic devices, warm objects, sunelectronic detectors, special photographic film, blackened thermometer0.1mm (10-4m)magic eyes in security lighting, remote control (eg TV)burning, if concentrated
Light; Red, Orange, Yellow, Green, Blue, Indigo, Violetelectronic devices (LED), hot objects, suneye, photographic film, electronic devices (eg, LDR)0.001mm (10-6m)seeing, photography, worldwide communication using optical fibresburning, blindness if concentrated
Ultraviolet (UV)gas discharge, very hot objects, UV lamps, sunphotographic film0.00001mm (10-8m)sun-tan lamp, making ions, making vitamin D, water purification plants to kill bacteriasunburn, skin cancer
X-raysvery fast electrons hitting a metal targetphotographic film10-10mimaging defects in bones, hidden devicescell destruction, cell mutation, cancer
Gamma rays ( \gamma)radioactive nuclei decayingphotographic film, GM tube10-12mmedical tracers, killing cancerous cells, sterilisationcell destruction, cell mutation, cancer