• Tags: x-ray, moseley, characteristic
• Difficulty: Advanced

X-rays are produced when high-energy electrons strike a metal target. Two types: continuous spectrum (bremsstrahlung) and characteristic spectrum (line spectrum). The minimum wavelength of the continuous spectrum: λ_min = $\frac{hc}{eV}$ = 12400/V Å, where V is the accelerating voltage.

Moseley's law for characteristic X-rays: √f = a(Z - b), where a and b are constants (b ≈ 1 for K-series, b ≈ 7.4 for L-series). This is equivalent to 1/λ = R(Z-b)^{2}(1/$n_{1}^{2}$ - 1/$n_{2}^{2}$). K-alpha X-ray: electron from L shell fills K shell vacancy. The effective nuclear charge is Z-1 (screening by the remaining K electron). JEE sometimes connects this to the hydrogen-like model.