Two parallel plates of length 8 cm each are spaced 3 mm apart. The plates are connected to an electrical voltage. An electron flies between the plates at a speed of 80,000 km/s so that upon entering, the track of its motion is parallel to the plates and is located next to the negatively charged plate. What is the voltage between the plates so that the electron will just hit the positively charged plate after the flight?
The charge of an electron is 
and the mass is 
.
