Image. The figure shows Kα and Kβ characteristic X-rays along with the continuous X-ray spectrum. Find the energy of the Lα X-ray. Take hc = 12420 eV·Å.
Physics · Atomic Structure and X-rays
JEE Mains Advanced

Question

Image. The figure shows Kα and Kβ characteristic X-rays along with the continuous X-ray spectrum. Find the energy of the Lα X-ray. Take hc = 12420 eV·Å.

G1 Physics · Accepted Answer

From the graph, the Kα and Kβ photon energies are hc/λ at the marked wavelengths. The shell-energy differences satisfy E(Kβ)=E(Kα)+E(Lα). Thus E(Lα)=E(Kβ)−E(Kα). Substituting the two wavelengths from the figure gives 6210 eV.