1 0:48 Pocahontas Trailer Pocahontas When English settlers land on the shores of her village, a free-spirited girl wonders what history-changing adventures await.
The gray (Gy), which is the SI unit of absorbed dose, corresponds to the absorption of 1 J of energy per kilogram of tissue. The rad (radiation absorbed dose) corresponds to the absorption of 1 10â2 J of energy per kilogram of tissue. Thus, 1 Gy = 100 rads. The rad is the unit most often used in medicine.
95% of the UV energy hitting the earthâs surface is UV-A. The other 5% is UV-B. In fact, almost all of UV-B radiation is absorbed by our atmosphere (Ah, the wonders of an ozone layer). UV-A penetrates the skin more deeply than UV-B, however, its UV-B that causes more short term and long term problems. Problems like skin cancer, aging, and DNA damage. Itâs also UV-B waves that are primarily responsible for your sunburned skin. How do these rays cause erythema and the pain that comes with it? UV-B wavelengths donât penetrate very deeply, but they cause photochemical reactions in your epidermis (the outer layer of your skin) and damages DNA.