Calculate the wavelength of the $K_{\alpha}$ line for $Z=31$, given $a=5 \times 10^7 \text{ Hz}^{1/2}$ for a characteristic $X$-ray spectrum.

If the energy of a $K$-shell electron is $-40000 \ eV$ and a potential of $60000 \ V$ is applied to a Coolidge tube,which of the following $X$-rays will be formed?

Moseley measured the frequency $(f)$ of the characteristic $X$-rays from many metals of different atomic number $(Z)$ and represented his results by a relation known as Moseley's law. This law is ($a, b$ are constants)

$X$-rays can be used to study crystal structure if the wavelength lies in the range:

The wavelength of the $K_{\alpha}$ line for an element with atomic number $57$ is $\lambda$. What will be the wavelength of the $K_{\alpha}$ line for an element with atomic number $29$?

The wavelength of the $L_\alpha$ $X$-ray line of $Pt^{78}$ is $1.32 \, \mathring A$. The wavelength of the $L_\alpha$ line in the $X$-ray spectrum of another unknown element is $4.17 \, \mathring A$. If the screening constant for the $L_\alpha$ line is $7.4$,then the atomic number of the unknown element is: