Question

If two atoms have their atomic numbers $z_1$and$z_2$. The ratio of the wavelengths ${\lambda }_1$ and ${\lambda }_2$ corresponding to their $K_{\alpha }$ lines is

• A. $\frac{z_1^2}{z_2^2}$
• B. $\frac{z_2^2}{z_2^1}$
• C. $\frac{z_1}{z_2}$
• D. $\frac{z_2}{z_1}$

Answer 1

Answer: (B)

$\frac{z_2^2}{z_2^1}$

for continuous X-Rays
${\lambda }_{K_{\alpha }}=\frac{hc}{E_K-E_L}$
$E=-13.6\frac{z^2}{n^2}$
$so\frac{{\lambda }_1}{{\lambda }_2}=\frac{z_2^2}{z_1^2}$