Question

There are two categories of ultraviolet light. Ultraviolet A ( UVA ) has a wavelength ranging from 320nm to 400nm . It is not so harmful to the skin and is necessary for the production of vitamin D. UVB, with a wavelength between 280nm and 320nm , is much more dangerous, because it causes skin cancer

PART A
Find the frequency ranges of UVA.
Enter your answers separated with commas.

fmin,fmax= 7.50

Answer 1

a)f=c/λ

Range=3*10⁸/400*10^-9 to 3*10⁸/320*10^-9

=7.5*10¹⁴,9.375*10¹⁴

b)Range=9.375*10¹⁴,1.07*10¹⁵

c)Wave number=2π/λ

Range=1.57*10⁷,1.96*10⁷

d)Range=1.96*10⁷,2.24*10⁷