Question

$K_{\alpha }$ wavelength emitted by an atom of atomic number Z = 11 is $\lambda$ Find the atomic number for an atom that emits $K_{\alpha }$ radiation with wavelength 4$\lambda$.

• A. 4
• B. 5
• C. 6
• D. 7

Answer 1

The correct option is C 6

$\frac{1}{\lambda }\alpha (Z-1{)}^{2}Sinceh{v}_{k_{\alpha }}=13.6eV(z-1{)}^2(\frac{1}{l^2}-\frac{1}{m^2})\Rightarrow \frac{{\lambda }_1}{{\lambda }_2}=\frac{(x_2-1{)}^2}{(x_1-1{)}^2}\Rightarrow \frac{\lambda }{4\lambda }={\left(\frac{z_2-1}{11-1}\right)}^2\Rightarrow \frac{10}{2}=z_2-1\Rightarrow z_2=6$