Question

An X-ray tube is operating at $12\text{kV}$ and $5\text{mA}$. Calculate speed of electrons (Approx.) striking the target $\left(\text{in order of}{10}^7\text{m/s}\right).$

Answer 1

Speed of electron is given by
$v=\sqrt{\frac{2\text{eV}}{m_e}}$
$v=\sqrt{\frac{2\times 1.6\times {10}^{-19}\times 12\times {10}^3}{9.1\times {10}^{-31}}}$
$v\approx 6\times {10}^7\text{m/s}$