What Is the Wavelength of the L Absorption Edge for Uranium?

[gfxroad]

Homework Statement

In uranium (Z=92) the K absorption edge is 0.107 Å and the Kα line is 0.126 Å. Determine the wavelength of the L absorption edge.

Homework Equations

K-edge: E_K= (Z-1)²*13.6
L-edge: E_L= (Z-σL)²*13.6*1/4
what is σ and how was calculated.
Characteristic X-rays: E_x = h*ν= h*c/λ= ΔE^kin = E_kin(i)-E_kin(f)
Bremsstrahlung: E_max=E_kin(i)

The Attempt at a Solution

λ_L= 0.71 Å

 

[gfxroad]

Any answer or clearance for this question please?