The electromagnetic spectrum is the range of all types of electromagnetic radiation. Radiation is energy that travels and spreads out as it goes. Examples of electromagnetic rations include the visible light that comes from a lamp in your house and the radio waves that come from a radio station. The electromagnetic spectrum contains other types, including microwaves, infrared light, ultraviolet light, X-rays, and gamma rays.
Gamma ray: Gamma-ray imaging is used by medical professionals to visualize the internal structures of the human body. The universe stands as the largest producer of gamma rays.
X-ray: X-rays are utilized by dentists for dental imaging and by airport security for baggage inspection. Additionally, X-rays are emitted by hot gases in the Universe.
Ultraviolet: The Sun emits ultraviolet radiation, which is responsible for skin tanning and burns. Moreover, “hot” objects in space also emit ultraviolet radiation.
Visible: Our eyes detect visible light. Fireflies, light bulbs, and stars all emit visible light.
Infrared: Night vision goggles detect the infrared light emitted by our skin and objects that emit heat. In space, infrared light aids in mapping the interstellar dust located between stars.
Microwave: Microwave radiation is capable of quickly cooking food, yet it is also used by astronomers to gain insights into the structure of nearby galaxies.
Radio: Your radio captures radio waves emitted by radio stations, allowing you to enjoy your favourite tunes. Additionally, radio waves are emitted by stars and gases in space.
Energy levels at different types of radiation:
Electromagnetic radiation is characterised by the stream of photons. Photons are mass-less particles that travel in wave-like patterns at the speed of light. Each photon carries a specific amount of energy, and the various types of radiation are distinguished by the energy levels of their photons. Generally, longer wavelengths correspond to lower energy. For example, radio waves has the lowest energy, followed by slightly more energetic microwave photons, then infrared, visible light, ultraviolet, X-rays, and finally, the most energetic of all, gamma-rays.
Reference: NASA
Read about units used for measuring electromagnetic radiation.
Read about NIR spectroscopy, hyperspectral and multispectral imaging using near-infrared radiations.