- Electromagnetic radiation (EM radiation or EMR) includes radio waves, microwaves, infrared, (visible) light, ultraviolet, X-rays, and gamma rays.
- Electromagnetic radiation is also called EM radiation, EMR and electromagnetic radiant energy.
- Man-made technologies that produce electromagnetic radiation include radio and TV transmitters, radar, MRI scanners, microwave ovens, computer screens, cellular phones, all types of lights and lamps, electric blankets, electric bar heaters, lasers, x-ray machines.
- In the quantum scale of electromagnetism, electromagnetic radiation consists of photons which are the elementary particles responsible for all electromagnetic phenomena.
- The quantum theory of electromagnetism helps to explain the transition of electrons to lower energy levels in an atom and black-body radiation.
- A single gamma ray photon might carry ~100,000 times the energy of a single photon of visible light.