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Highest ultraviolet index measured: On 29 December 2003, a UV index of 43.3 was detected at Chile/Bolivia's Licancabur volcano, at 19,423 feet (5,920 m) altitude. A light-skinned individual in such conditions may experience moderate sunburn in as little as 4 minutes.
When the UV index is presented on a daily basis, it represents UV intensity around the sun's highest point in the day, called solar noon, halfway between sunrise and sunset. This typically occurs between 11:30 and 12:30, or between 12:30 and 13:30 in areas where daylight saving time is being observed.
The lasing medium is a semiconductor chip. Frequency doubling or tripling is typically done to produce visible or ultraviolet radiation. Power levels of several watts are possible. Beam quality can be extremely high- often rivaling that of an ion laser.
Extreme ultraviolet composite image of the Sun (red: 21.1 nm, green: 19.3 nm, blue: 17.1 nm) taken by the Solar Dynamics Observatory on August 1, 2010 13.5 nm extreme ultraviolet light is used commercially for photolithography as part of the semiconductor fabrication process.
With the exception of Madrid, [9] Lisbon [10] and Athens, [11] Rome has the highest UV index between European capitals (only in the continent) and values close to that of Chicago at 41.9 °N as ultraviolet radiation is less interfered with by other geographic variables, but with a moderate annual average with index equal to 5, which allows ...
[43] [failed verification] UVC is the highest-energy, most-dangerous type of ultraviolet radiation, and causes adverse effects that can variously be mutagenic or carcinogenic. [44] Despite the importance of the sun to vitamin D synthesis, it is prudent to limit the exposure of skin to UV radiation from sunlight [45] and from tanning beds. [46]
Luminous efficacy can be normalized by the maximum possible luminous efficacy to a dimensionless quantity called luminous efficiency.The distinction between efficacy and efficiency is not always carefully maintained in published sources, so it is not uncommon to see "efficiencies" expressed in lumens per watt, or "efficacies" expressed as a percentage.
The amount of UV that is generated from a low-pressure lamp is highly dependent on the temperature in the tanning unit. As a rule, tanning lamps produce the highest amount of ultraviolet light when this temperature is between 90 and 110 °F (32 and 43 °C). As the temperature moves away from this range, the amount of UV produced is reduced.