Ultraviolet Radiation, there are two categories of ultraviolet light. Ultraviolet A (UVA) bas a wavelength ranging from

Question:

Ultraviolet Radiation, there are two categories of ultraviolet light. Ultraviolet A (UVA) bas a wavelength ranging from 320 nm to 400 nm. It is not so harmful to the skin and is necessary for the production of vitamin D. UVB, with a wavelength between 280 nm and 320 nm, is much more dangerous because it causes skin cancer.
(a) Find the frequency ranges of UVA and UVB.
(b) What are the ranges of the wave numbers for UVA and UVB?