The graph between the square root of the frequency of a characteristic line in the $X$-ray spectrum and the atomic number of the target is:

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?

The wavelength of $X$-rays is of the order of .......

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 .......

The minimum wavelength of the $X$-rays produced at an accelerating potential $V$ is $\lambda$. If the accelerating potential is changed to $2V$, then the minimum wavelength would become:

If the frequency of the $K_\alpha$ line of an element with $Z = 64$ is $\nu_\alpha$ and the frequency of the $K_\alpha$ line of an element with $Z = 80$ is $\nu'_\alpha$,then the ratio of their frequencies is: