Sunburn is caused by UV radiation, either from the sun or from artificial sources, such as tanning lamps, welding arcs, or ultraviolet germicidal irradiation. It is a reaction of the body to direct DNA damage from UVB light. This damage is mainly the formation of a thymine dimer.xcessive UV radiation is the leading cause of primarily non-malignant skin tumors. Sunscreen is widely agreed to prevent sunburn and some types of skin cancer. Clothing, including hats, is considered the preferred skin protection method.
A protractor is used to measure angles. When surveying a theodolite is used. There are a number of tools on the market that perform angle measurement. A <b>protractor</b> is used to measure angles.<br />When surveying a <b>theodolite</b> is used.<br />There are a number of tools on the market that perform angle measurement. Minor edit?
Micrometers are typically used in manufacturing, machining, and mechanical engineering. There are three types of micrometer: outside, inside, and depth. Outside micrometers may also be called micrometer calipers, and are used to measure the length, width, or outside diameter of an object. Inside micrometers are typically used to measure interior diameter, as in a hole. Depth micrometers measure the height, or depth, of any shape that has a step, groove, or slot.