Question

Select the correct arrangement of the types of ultraviolet radiations according to the intensity of their effect on human skin.

• A. UV-A > UV-B > UV-C
• B. UV-B > UV-C > UV-A
• C. UV-C > UV-B > UV-A
• D. UV-A > UV-C > UV-B

Answer 1

Answer: (B)

UV-B > UV-C > UV-A

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) are absorbed by the armosphere. The longer ones are not much harmful. 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.

So, the correct answer is 'UV-B > UV-C > UV-A'.