The Kα X-ray emission line of tungsten occurs at  λ = 0.021 nm. The energy difference between K and L levels in this atom is about

0.51Mev 1.2MeV 59KeV 13.6MeV

59KeV

$\text{Energy difference betweel K and L level is given by } \lambda_{K_{\alpha}} = \frac{hc}{E_K - E_L}$ $E_K - E_L = \frac{1240 eV}{0.021} = 59KeV$