The ratio of the energy of the photon emitted by the $K_{\alpha}$ line to that of the $K_{\beta}$ line is

$\Delta \lambda$ is the difference between the wavelength of the $K_\alpha$ line and the minimum wavelength of the continuous $X$-ray spectrum when the $X$-ray tube is operated at a voltage $V$. If the operating voltage is changed to $V / 3$,then the above difference is $\Delta \lambda^{\prime}$. Then:

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 structure of solids is investigated by using

When a metal target is bombarded with high-energy electrons,the electromagnetic waves generated are

When cathode rays strike a metal target with a high melting point and high atomic number,what is produced?