An electron enters the region between two plates traveling along the x-direction with a speed of v = 4.78 * 10⁶ m/s.Both plates are parallel to the x-y plane and are separated by 4.5 cm.The potential of the top plate at z = 4.5 cm is +100 V while the potential of the bottom plate at z = 0 cm is 0 V.What is the direction of the magnetic field between the plates that is required so that the electron continues traveling in a straight line along the x-direction in this region?

Question

Quizplus · Accepted Answer

To keep the electron moving in a straight line along the x-direction, the magnetic field must counteract the electric force pushing the electron towards or away from the plates. Since the electric field between the plates is directed from the positive to the negative plate (z-direction), and the electron is moving in the x-direction, the magnetic force must be perpendicular to both the direction of motion (x) and the electric field (z). According to the right-hand rule, for a negatively charged electron, the magnetic field that would cause the required force direction is in the negative y-direction.

An Electron Enters the Region Between Two Plates Traveling Along