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)

Let ${\lambda _\alpha }$,${\lambda _\beta }$ and ${\lambda '_\alpha }$ denote the wavelengths of the $X-$ rays of the ${K_\alpha }, {K_\beta }$ and ${L_\alpha }$ lines in the characteristic $X-$ rays for a metal.

The shortest wavelength of $X$-rays emitted from an $X$-ray tube depends on the

If $X$-rays pass through a strong magnetic field,the $X$-rays . . . . . .

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:

Absorption of $X$-rays is maximum in which of the following different sheets?