An electron traveling north enters a region where the electric field is uniform and points North. The electron:
Solution
Direction of force on an electron in an electric field:
An electron is a negatively charged particle.
The lines of an electric field point towards the direction in which the field applies force on a positively charged particle.
For a negatively charged particle, the field exerts force in the opposite direction of the field lines.
Thus, an electron moving north will slow down and eventually reverse its direction if it enters an electric field that points north.