Answer
$9.15\times10^{6}m/s$.
Work Step by Step
Use the principle of energy conservation. The initial potential energy changes to kinetic energy of the electron when the electron is far away, where PE = 0.
The electrical force equals the gravitational attraction.
$$PE_i=KE_f$$
$$k\frac{(-e)(Q)}{r}= \frac{1}{2}mv^2$$
$$v=\sqrt{ \frac{2k(-e)Q}{mr}}$$
$$v=\sqrt{\frac{2(8.988\times10^{9}) (-1.60\times10^{-19}C)(-6.50\times10^{-9}C) }{(9.11\times10^{-31}kg)(0.245m)}}$$
$$= 9.15\times10^{6}m/s $$