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  2. Ultraviolet - Wikipedia

    en.wikipedia.org/wiki/Ultraviolet

    Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight , and constitutes about 10% of the total electromagnetic radiation output from the Sun.

  3. Ultraviolet index - Wikipedia

    en.wikipedia.org/wiki/Ultraviolet_index

    Average UV at noon 1996-2002 (European Space Agency) The ultraviolet index, or UV index, is an international standard measurement of the strength of the sunburn-producing ultraviolet (UV) radiation at a particular place and time. It is primarily used in daily and hourly forecasts aimed at the general public.

  4. Electromagnetic spectrum - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_spectrum

    In frequency (and thus energy), UV rays sit between the violet end of the visible spectrum and the X-ray range. The UV wavelength spectrum ranges from 399 nm to 10 nm and is divided into 3 sections: UVA, UVB, and UVC. UV is the lowest energy range energetic enough to ionize atoms, separating electrons from them, and thus causing chemical reactions.

  5. Electromagnetic radiation - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_radiation

    UV, with X-ray and gamma radiation, are referred to as ionizing radiation due to the ability of photons of this radiation to produce ions and free radicals in materials (including living tissue). Since such radiation can severely damage life at energy levels that produce little heating, it is considered far more dangerous (in terms of damage ...

  6. Lyman series - Wikipedia

    en.wikipedia.org/wiki/Lyman_series

    In physics and chemistry, the Lyman series is a hydrogen spectral series of transitions and resulting ultraviolet emission lines of the hydrogen atom as an electron goes from n ≥ 2 to n = 1 (where n is the principal quantum number), the lowest energy level of the electron (groundstate).

  7. Extreme ultraviolet - Wikipedia

    en.wikipedia.org/wiki/Extreme_ultraviolet

    Extreme ultraviolet radiation (EUV or XUV) or high-energy ultraviolet radiation is electromagnetic radiation in the part of the electromagnetic spectrum spanning wavelengths shorter than the hydrogen Lyman-alpha line from 121 nm down to the X-ray band of 10 nm.

  8. Ultraviolet photoelectron spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Ultraviolet_photoelectron...

    With this source, Turner's group obtained an energy resolution of 0.02 eV. Turner referred to the method as "molecular photoelectron spectroscopy", now usually "ultraviolet photoelectron spectroscopy" or UPS. As compared to XPS, UPS is limited to energy levels of valence electrons, but measures them more accurately

  9. Balmer series - Wikipedia

    en.wikipedia.org/wiki/Balmer_series

    Lines five and six can be seen with the naked eye, but are considered to be ultraviolet as they have wavelengths less than 400 nm. The Balmer series , or Balmer lines in atomic physics , is one of a set of six named series describing the spectral line emissions of the hydrogen atom .