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Select the correct arrangement of the types of ultraviolet radiations according to the intensity of their effect on human skinA. `UV-A gt UV-B gt UV-C`B. `UV-B gt UV-C gt UV-A`C. `UV-C gt UV-B gt UV-A`D. `UV-A gt UV-C gt UV-B` |
Answer» Correct Answer - B Ultraviolet radiations are of three types -UV-C (100-280 nm), UV-B (280-320 nm) and UV-A (320-390 nm). Shorter ultraviolet radiations (UV-C) ar absorbed by the atmosphere. The longer ones are not much hjarmful. The intermediate or UV-B are harmful as well as capable of deep penetration. Thinning of ozone layer increases the amount of UV-B radiations reaching the earth. UV-B radiations damage skin cells cause ageing of skin and skin cancer. |
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