The shortest $K$-line for tungsten is 0.015 nm , the energy difference between the $K$ and $L$ level

Question

The shortest $K$-line for tungsten is 0.015 nm , the energy difference between the $K$ and $L$ levels of this atom is

Professor PC Thomas Classes · Answer

The energy of $K$-shell is $E=-\frac{1240}{0.015}=-82.6 \mathrm{keV}$ ∴ Energy between $K$ and $L$ shell is $ E_{2-1}=\frac{3}{4}(82.6)=62 \mathrm{keV} $