Electromagnetic radiation
In physics, electromagnetic radiation (EMR) or electromagnetic wave (EMW) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency (inversely proportional to wavelength), ranging from radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, to gamma rays. All forms of EMR travel at the speed of light in a vacuum and exhibit wave–particle duality, behaving both as waves and as discrete particles called photons.
Extends: [Electromagnetic radiation](https://wikipedia.org.ai/Electromagnetic radiation), [Heinrich Hertz](https://wikipedia.org.ai/Heinrich Hertz), Radiation