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  2. Electromagnetic spectrum - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_spectrum

    Longer-wavelength radiation such as visible light is nonionizing; the photons do not have sufficient energy to ionize atoms. Throughout most of the electromagnetic spectrum, spectroscopy can be used to separate waves of different frequencies, so that the intensity of the radiation can be measured as a function of frequency or wavelength.

  3. Visible spectrum - Wikipedia

    en.wikipedia.org/wiki/Visible_spectrum

    Electromagnetic radiation in this range of wavelengths is called visible light (or simply light). The optical spectrum is sometimes considered to be the same as the visible spectrum, but some authors define the term more broadly, to include the ultraviolet and infrared parts of the electromagnetic spectrum as well, known collectively as optical ...

  4. Electromagnetic radiation - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_radiation

    Natural sources produce EM radiation across the spectrum. EM radiation with a wavelength between approximately 400 nm and 700 nm is directly detected by the human eye and perceived as visible light. Other wavelengths, especially nearby infrared (longer than 700 nm) and ultraviolet (shorter than 400 nm) are also sometimes referred to as light.

  5. Radio spectrum - Wikipedia

    en.wikipedia.org/wiki/Radio_spectrum

    The lowest frequencies used for radio communication are limited by the increasing size of transmitting antennas required. [6] The size of antenna required to radiate radio power efficiently increases in proportion to wavelength or inversely with frequency. Below about 10 kHz (a wavelength of 30 km), elevated wire antennas kilometers in diameter ...

  6. Emission spectrum - Wikipedia

    en.wikipedia.org/wiki/Emission_spectrum

    The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to electrons making a transition from a high energy state to a lower energy state. The photon energy of the emitted photons is equal to the energy difference between the two states. There are many possible ...

  7. Absorption band - Wikipedia

    en.wikipedia.org/wiki/Absorption_band

    Absorptions bands in the Earth's atmosphere created by greenhouse gases and the resulting effects on transmitted radiation.. In spectroscopy, an absorption band is a range of wavelengths, frequencies or energies in the electromagnetic spectrum that are characteristic of a particular transition from initial to final state in a substance.

  8. Far infrared - Wikipedia

    en.wikipedia.org/wiki/Far_infrared

    This places far infrared radiation within the CIE IR-B and IR-C bands. [1] The longer wavelengths of the FIR spectrum overlap with a range known as terahertz radiation. [2] Different sources may use different boundaries to define the far infrared range. For instance, astronomers often define it as wavelengths between 25 μm and 350 μm. [3]

  9. Photon energy - Wikipedia

    en.wikipedia.org/wiki/Photon_energy

    Photon energy is the energy carried by a single photon. The amount of energy is directly proportional to the photon's electromagnetic frequency and thus, equivalently, is inversely proportional to the wavelength. The higher the photon's frequency, the higher its energy. Equivalently, the longer the photon's wavelength, the lower its energy.