The wavelength `lambda` of the `K_(a)` line of characteristic `X` - ray spectra varies with atomic number approximately

Options

A. `lambda prop Z`
B. `lambda_(1) prop sqrt(Z)`
C. `lambda prop (1)/(Z^(2))`
D. `lambda prop (1)/(sqrt(Z))`

Answer

C

Explanation

According to Mosley's law `v = a(Z - b)^(2)` and `v prop (1)/(lambda)`