Physics - Electromagnetic Spectrum

The electromagnetic spectrum

The electromagnetic spectrum is a continuous range of wavelengths. The types of radiation that occur in different parts of the spectrum have different uses and dangers - depending on their wavelength and frequency.

Refraction from a prism

The order of electromagnetic waves in the spectrum is shown in the table.

Energy	Frequency	Wavelength	Radiation type	Typical use
Lowest	Lowest	Longest	Radio waves	Television signals
			Microwaves	Cooking, mobile phones
			Infrared	Optical fibre communication
			Visible light	Seeing
			Ultraviolet	Detecting forged bank notes
			X-rays	Medical images of bones
Highest	Highest	Shortest	Gamma radiation	Killing cancer cells

Radio waves have the lowest frequencies and longest wavelengths, while gamma waves have the highest frequencies and shortest wavelengths.

All of these waves travel at the same speed in free space, which is the speed of light or about 300,000,000 m/s (metres per second).