Final answer:
The electron is accelerating due to the perpendicular force exerted by the magnetic field in the z direction, which disrupts its motion in the xy plane. The magnitude of the force and the presence of a magnetic field indicate that the electron is neither stationary nor in equilibrium and that the magnetic field is not zero.
Step-by-step explanation:
Magnetic Force and Electron Trajectory
An electron moving in the xy plane under the influence of a magnetic field in the z direction will experience a magnetic force perpendicular to both its velocity and the magnetic field. If an electron is moving with a velocity v in a magnetic field B, the magnetic force F acting on it can be determined using the formula F = qvBsinθ, where q is the charge of the electron, v is the velocity, B is the magnetic field strength, and θ is the angle between the velocity vector and the magnetic field.
Considering the given information, the force of 5.50×10⁻¹⁸ N in the y direction implies that the electron is not stationary (option a) nor in equilibrium (option b), for equilibrium would mean the net force is zero. The magnetic field is not zero (option c), since it is given as 0.200 T. Thus, since the electron experiences a force, it must be accelerating (option d), as per Newton's second law of motion.