$X$-rays are produced due to which of the following?

The potential difference applied to an $X$-ray tube is $5 \ KV$ and the current through it is $6.4 \ mA$. The number of electrons striking the target per second is:

The energy of a photon of light with wavelength $5000\,\mathring{A}$ is approximately $2.5\,\text{eV}$. In this way,the energy of an $X$-ray photon with wavelength $1\,\mathring{A}$ would be:

Solid targets of different elements are bombarded by highly energetic electron beams. The frequency $(f)$ of the characteristic $X-$rays emitted from different targets varies with atomic number $Z$ as

If the potential difference $V$ applied to the Coolidge tube is doubled, then the cut-off wavelength

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.