Question

If the potential difference applied to an $X$-ray tube is $5\, kV$ and the current through it is $6.4\, mA$, then number of electrons striking the target per second is $y \times 10^{16}$. Find $y$.

Answer 1

$n e=I$
$n \times 1.6 \times 10^{-19}=6.4 \times 10^{-3}$
$ \Rightarrow n=4 \times 10^{16} / s$