Q. How long is the Marriage License valid?A. A Marriage License is valid for 60 days, beginning the day after it is issued. Members of the armed forces who can prove they are on active duty at the time of applying for the Marriage License can obtain a Marriage License valid for 180 days.
Lesson Summary. UV light is one type of electromagnetic wave. Other electromagnetic waves include radio waves, microwaves, visible light, and X-rays. UV light is used by humans to produce vitamin D, but overexposure to UV light can damage DNA and cause painful sunburns, cataracts, and skin cancer.
UV Light. UV light is measured in microwatts of ultraviolet radiation per lumen of visible light (ÂµW/l). The high energy of UV radiation is particularly damaging to artifacts. UV light is not visible to the human eye and therefore removing it from museum lighting causes no change in appearance. Daylight is generally the strongest source of UV light; fluorescent, metal halide and mercury vapor lights also emit UV radiation.