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  2. Ultraviolet index - Wikipedia

    en.wikipedia.org/wiki/Ultraviolet_index

    Sunburn effect (as measured by the UV index) is the product of the sunlight power spectrum (radiation intensity) and the erythemal action spectrum (skin sensitivity) across the range of UV wavelengths. [9] [10] The UV index is a number linearly related to the intensity of sunburn-producing UV radiation at a given point on the Earth's surface.

  3. Ultraviolet - Wikipedia

    en.wikipedia.org/wiki/Ultraviolet

    The WHO-standard ultraviolet index is a widely publicized measurement of total strength of UV wavelengths that cause sunburn on human skin, by weighting UV exposure for action spectrum effects at a given time and location. This standard shows that most sunburn happens due to UV at wavelengths near the boundary of the UVA and UVB bands.

  4. Health effects of sunlight exposure - Wikipedia

    en.wikipedia.org/wiki/Health_effects_of_sunlight...

    On the positive side, UV exposure enables the synthesis of vitamin D 3, which is essential for bone health [1] and potentially plays a role in inhibiting certain cancers. [ 2 ] [ 3 ] While vitamin D can also be obtained through dietary supplements, [ 4 ] UV exposure offers benefits such as enhanced subdermal nitric oxide production and improved ...

  5. Cauchy's equation - Wikipedia

    en.wikipedia.org/wiki/Cauchy's_equation

    The most general form of Cauchy's equation is = + + +,where n is the refractive index, λ is the wavelength, A, B, C, etc., are coefficients that can be determined for a material by fitting the equation to measured refractive indices at known wavelengths.

  6. Sunburn - Wikipedia

    en.wikipedia.org/wiki/Sunburn

    Sunburn is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet (UV) radiation, usually from the Sun.Common symptoms in humans and other animals include red or reddish skin that is hot to the touch or painful, general fatigue, and mild dizziness.

  7. Refractive index - Wikipedia

    en.wikipedia.org/wiki/Refractive_index

    A gradient-index lens with a parabolic variation of refractive index (n) with radial distance (x). The lens focuses light in the same way as a conventional lens. If the refractive index of a medium is not constant but varies gradually with the position, the material is known as a gradient-index (GRIN) medium and is described by gradient index ...

  8. Atmospheric tide - Wikipedia

    en.wikipedia.org/wiki/Atmospheric_tide

    Therefore, each wavenumber/frequency pair (a tidal component) is a superposition of associated Hough functions (often called tidal modes in the literature) of index n. The nomenclature is such that a negative value of n refers to evanescent modes (no vertical propagation) and a positive value to propagating modes.

  9. Optical properties of water and ice - Wikipedia

    en.wikipedia.org/wiki/Optical_properties_of...

    The refractive index of water at 20 °C for visible light is 1.33. [1] The refractive index of normal ice is 1.31 (from List of refractive indices).In general, an index of refraction is a complex number with real and imaginary parts, where the latter indicates the strength of absorption loss at a particular wavelength.