The order of voltage applied across the ends of an $X$-ray tube is ...... $V$.

The minimum wavelength of $X$-rays produced by an $X$-ray tube depends on which of the following?

$X$-rays will travel the minimum distance in which of the following materials?

In tungsten,the energy of a $K$-shell electron is $20 \, keV$ and that of an $L$-shell electron is $2 \, keV$. When an electron jumps from the $L$ shell to the $K$ shell,the wavelength of the emitted $X$-ray photon will be:

The energy of the $K_\alpha$ $X$-ray line of an element is $8578$ units,and the energy of the $L$ level is $-2859$ units. The energy of the $K$ level is . . . . . . units.

For harder $X$-rays: