Cambridge O Level Physics · Syllabus 5054 · Waves
Electromagnetic Spectrum
What is Electromagnetic Spectrum?
The electromagnetic spectrum is the continuous family of transverse waves that all travel at three times ten to the eight metres per second in a vacuum and need no medium, arranged in order of frequency as radio, microwave, infrared, visible, ultraviolet, X-ray and gamma.
This definition is part of the Waves chapter in Cambridge O Level Physics.
Electromagnetic Spectrum in context
The electromagnetic spectrum is one continuous family of transverse waves that all travel at \(3.0 \times 10^{8}\) m/s in a vacuum (and at approximately the same speed in air), transfer energy, and need no material medium. In order of increasing frequency and therefore decreasing wavelength the main regions are: radio, microwave, infrared, visible, ultraviolet, X-ray, gamma. Each region is used for the jobs its particular frequency and wavelength suit, and the hazards rise sharply at the high-frequency end, where the radiation becomes ionising.