`X`-rays are produced by accelerating electrons by voltage `V` and let they strike a metal of atomic number `Z` . The highest frequency of `X - rays` produced is proportional to

Options

A. V
B. Z
C. `(Z-1)`
D. `(Z-1)^2`

Answer

D

Explanation

Mosley’s law 
`f prop (Z-b)^2`
For `k_(alpha) ` line , b =1
`f_("max") prop (Z-1)^2`