$X$-rays were discovered by

An electron beam is accelerated by a potential difference of $V$ and strikes a metal target to produce $X$-rays. For which of the following values of $V$ (in $kV$) will the $X$-ray wavelength be the shortest?

Hydrogen atom does not emit $X$-rays because

For the study of bone fractures,the minimum wavelength of $X$-rays should be $10^{-11} \ m$. The accelerating voltage for electrons in the $X$-ray machine will be .......

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

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) $[h = 4.14 \times 10^{-15} \, eVs, c = 3 \times 10^{8} \, ms^{-1}]$