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Electromagnetic spectrum
Similar term(s): Gamma rays, Radio waves, Visible light, Blue light, Infrared radiation, Ultraviolet radiation.
Definition:
The electromagnetic spectrum is the entire range of wavelengths of all knownelectromagnetic radiations. It includes:
Gamma rays have the smallest wavelengths and highestfrequencies known. They are high energy waves capable of travelling longdistances through air and are the most penetrating waves.
X-rays have longer wavelengths than gamma rays but smallerwavelengths and therefore higher energy than ultraviolet radiation. They havebeen used in various applications in science and industry and are primarily usedin medicine for instance in radiography. They are a form of ionizing radiationand as such can be dangerous. X-rays are emitted by electrons outside thenucleus, while gamma rays are emitted by the nucleus.
Ultraviolet (UV) radiation is defined as the portion of theelectromagnetic spectrum between X-rays and visible light.More...
Visible light – also known as the visible spectrum – is theportion of the electromagnetic spectrum that human eyes can detect. It coversall colours from blue at 400 nm to red at 700 nm, with blue light having moreenergy than red light.
Infrared (IR) radiation – also referred to as thermalradiation – is the portion of the electromagnetic spectrum lying between visiblelight and microwaves. The most important natural source of infrared radiation isthe sun.
Radio waves have long wavelengths, ranging from a fewcentimetres to many thousands of kilometres in length. They are used among otherthings for television, cell phone and radio communications.
