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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.
The Sun's UV output is divided into UV-A and UV-B: solar UV-A flux is 100 times that of UV-B, but the erythema response is 1,000 times higher for UV-B. [citation needed] This exposure can increase at higher altitudes and when reflected by snow, ice, or sand. The UV-B flux is 2–4 times greater during the middle 4–6 hours of the day, and is ...
Most stars are actually relatively cool objects emitting much of their electromagnetic radiation in the visible or near-infrared part of the spectrum. Ultraviolet radiation is the signature of hotter objects, typically in the early and late stages of their evolution. In the Earth's sky seen in ultraviolet light, most stars would fade in prominence.
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The cheaper and more common 395 nm UV LEDs are much closer to the visible spectrum, and give off a purple color. Other UV LEDs deeper into the spectrum do not emit as much visible light. [ 41 ] LEDs are used for applications such as UV curing applications, charging glow-in-the-dark objects such as paintings or toys, and lights for detecting ...
Although present in space, this part of the UV spectrum is not of biological importance, because it does not reach living organisms on Earth. There is a zone of the atmosphere in which ozone absorbs some 98% of non-ionizing but dangerous UV-C and UV-B. This ozone layer starts at about 20 miles (32 km) and extends upward. Some of the ultraviolet ...
Download and install the latest Java Virtual Machine in Internet Explorer. 1. Go to www.java.com. 2. Click Free Java Download. 3. Click Agree and Start Free Download. 4. Click Run. Notes: If prompted by the User Account Control window, click Yes. If prompted by the Security Warning window, click Run. 5.
A UV-Vis spectrophotometer is an analytical instrument that measures the amount of ultraviolet (UV) and visible light that is absorbed by a sample. It is a widely used technique in chemistry, biochemistry, and other fields, to identify and quantify compounds in a variety of samples.