If $V$ is the accelerating voltage,then the maximum frequency of continuous $X$-rays is given by

$X$-rays are produced in the laboratory by:

The wavelength of the $K\alpha$ line in copper is $1.54 \ \mathring{A}$. The ionization energy of the $K$ electron in copper in Joules is:

The $K_{\alpha}$ $X$-ray of molybdenum has a wavelength of $0.071 \, nm$. If the energy of a molybdenum atom with a $K$ electron knocked out is $27.5 \, keV$,the energy of this atom when an $L$ electron is knocked out will be $.... \, keV$. (Round off to the nearest integer) $[h = 4.14 \times 10^{-15} \, eVs, c = 3 \times 10^{8} \, ms^{-1}]$

The electron transition required for the emission of characteristic $K_\beta$ $X$-rays is:

Characteristic $X$-rays are not obtained in the spectrum of a hydrogen atom because,