Intensity of Cu K-alpha radiation (excitation voltage)

sh1t8ra1n

Hello there folks, I have some materials science HW I would like some help with. I need to find the intensity of Kα radiation based on the equation:
I_Kα = Bi(V_A - V_K)^1.5, where B is a machine dependent parameter, i is the tube current, V_A is applied voltage, V_K is excitation voltage. Also included in the problem is the fact that at 30kV applied voltage, the intensity is 90 times above the continuous spectrum. I need to determine the intensity at 50kV operating voltage. I have the binding energies of the Cu orbitals, but I do not know how to turn those into excitation voltage, and I do not know how to calculate the tube current, I assume you can find it from the operating voltage...?

Thanks for any suggestions or tips!