Question
The wavelengths of $\text{K}_\alpha$ and $\text{L}_\alpha$ X-rays of a material are 21.3pm and 141pm respectively. Find the wavelength of $\text{K}_\beta$ X-ray of the material.
✓
Answer
$\text{E}_1=\frac{1242}{21.3\times10^{-3}}=58.309\times10^3\text{eV}$$\text{E}_2=\frac{1242}{141\times10^{-3}}=8.8085\times10^3\text{eV}$
$\text{E}_3=\text{E}_1+\text{E}_2$
$\Rightarrow(58.309+8.809)\text{ev}=67.118\times10^3\text{ev}$
$\lambda=\frac{\text{hc}}{\text{E}_3}=\frac{1242}{67.118\times10^3}$
$=18.5\times10^{-3}\text{nm}=18.5\text{pm}$
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