The wave number (k) of a light wave can be calculated using the formula:
k = 2π / λ
Where λ is the wavelength of the light.
Given that the wavelength of the light is 200 Å (Angstroms), we can substitute this value into the formula:
k = 2π / 200 Å
To simplify the expression, we need to convert Ångstroms to meters since the SI unit for wavelength is meters. 1 Ångstrom is equal to 1 x 10^(-10) meters.
k = 2π / (200 x 10^(-10) m)
To evaluate the expression, we can perform the calculation:
k = 2π / 2 x 10^(-8) m
k = π x 10^8 m^(-1)
So, the wave number of the light with a wavelength of 200 Å is π x 10^8 m^(-1).