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Electromagnetic Spectrum

Electromagnetic Spectrum

Summary of electromagnetic spectrum

All electromagnetic waves can travel through vacuum. They all travel at the speed of 3 X 10^8 m/s in vacuum and very close to this value through air. 

In other materials however, they travel a bit slower. Each selection of the electromagnetic spectrum has its own uses and features:

RegionFrequency Range (Hz)Wavelength Range (M)Applications
Radio105 – 1010104 – 10-2Electromagnetic oscillations produced by electric circuits; Received by aerial and used in communication
Microwave1010 – 101110-2 – 10-3Used for rapid heating in microwave; Used to communicate with satellites i.e. mobile phones
Infra-red1011 – 101410-3 – 10-6All hot objects produce infrared; Used for night goggles, burglar alarms, etc. (since all humans emit infra-red)
Visible101410-7Produced by very hot objects such as the sun; Detected by the eye; Used in optical fibres communication
Ultraviolet1015 -101710-7 – 10-9Causes fluorescence in some materials; Uses with sunbeds to produce sun tan
X-Radiation1017 – 101910-9 – 10-11Blackens photographic film; Used in diagnosis (X-Ray scan); Dangerous in high doses
Gamma Radiation1019 – 102010-11 – 10-14Produced in nuclei of radioactive elements; Used in medical diagnosis but dangerous in high dosage

The higher the frequency, the higher the energy of the radiation. Therefore, radio waves have the lowest energy and gamma radiation has the highest energy within the spectrum.