In producing $X$-rays,a beam of electrons accelerated by a potential difference $V$ is made to strike a metal target. For what value of $V$ will the $X$-rays have the lowest wavelength of $0.3094 \ \mathring{A}$? (in $kV$)

The structure of solids is investigated by using

An electron beam strikes a target at an accelerating potential of $50 \,kV$. Which of the following frequencies of $X$-rays will not be obtained?

Intensity of $X-$rays depends upon the number of

The wavelength of $L_{\alpha}$ line in $X$-ray spectrum of $_{78}Pt$ is $1.32 \ \mathring{A}$. The wavelength of $L_{\alpha}$ line in $X$-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:

According to Moseley's law,the frequency of a spectral line in the $X$-ray spectrum varies as: