An electron is accelerated in a vacuum from rest through a potential difference of 850V.

Show that the final momentum of the electron is 1.6 × 10–23 N s.

Question

An electron is accelerated in a vacuum from rest through a potential difference of 850V.

Show that the final momentum of the electron is 1.6 × 10–23 N s.

anonymous · Answer

The motion of an electron with that energy is nonrelativistic, so you can feel free to use
$$ p = \sqrt{2mE } $$
where
$$ E = e\cdot \Delta V $$
$$ e = 1.6\cdot 10^{-19}  \text{ C} $$
$$\Delta V = 850 \text{ V }$$
$$ m = 9.1 \cdot 10^{-31} \text{ kg} $$