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The filters are selected so that the mean wavelengths of response functions (at which magnitudes are measured to mean precision) are 364 nm for U, 442 nm for B, 540 nm for V. Zero-points were calibrated in the B−V (B minus V) and U−B (U minus B) color indices selecting such A0 main sequence stars which are not affected by interstellar ...
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.
In astronomy, a photometric system is a set of well-defined passbands (or optical filters), with a known sensitivity to incident radiation.The sensitivity usually depends on the optical system, detectors and filters used.
UV classifications include UVA (320-400 nm), UVB (290-320 nm) and UVC (200-280 nm). UV-absorbing compounds are used not only in sunscreen, but also in other personal care products, such as lipstick, shampoo, hair spray, body wash, toilet soap, and insect repellent. [ 2 ]
Typical F71T12 71-inch, 100-watt, bi-pin tanning lamp. Ultraviolet radiation (UVR) is part of the electromagnetic spectrum, just beyond visible light.Ultraviolet wavelengths are 100 to 400 nanometres (nm, billionths of a metre) and are divided into three bands: A, B and C. UVA wavelengths are the longest, 315 to 400 nm; UVB are 280 to 315 nm, and UVC wavelengths are the shortest, 100 to 280 nm.
The action spectrum shows that UVA does not cause immediate reaction, but rather UV begins to cause photokeratitis and skin redness (with lighter skinned individuals being more sensitive) at wavelengths starting near the beginning of the UVB band at 315 nm, and rapidly increasing to 300 nm. The skin and eyes are most sensitive to damage by UV ...
Optical radiation is the part of the electromagnetic spectrum with wavelengths between 100 nm and 1 mm. [1] [2] This range includes visible light, infrared light, and part of the ultraviolet spectrum. [3] Optical radiation is non-ionizing, [4] and can be focused with lenses and manipulated by other optical elements.
Because UVC can be deadly, a special dichroic filter glass (usually purple) is required that will filter out the UVC and UVB. The goal with high-pressure tanning bulbs is to produce a high amount of UVA only. Unfiltered light from a high-pressure lamp is rich in UVC used in germicidal lamps, for water purification, but it damages human skin.