Final answer:
The force on an electron located on a 0-volt potential line would be directed to the left, due to the electron's negative charge and the nature of electric fields between parallel plates. The magnitude of the force cannot be determined without further information.
Step-by-step explanation:
The student's question pertains to the effect of electric fields and equipotential lines on a charged particle, in particular, an electron situated at a location of 0-volt potential. In a setup with two parallel plates connected to a battery, there will be electric field lines present between the plates.
The direction of the electric field will be from the positive to the negative plate, and the equipotential lines will be perpendicular to these field lines. According to physics principles, the force on a charged particle in an electric field is given by F = qE, where q is the charge of the particle and E is the electric field.
Since an electron has a negative charge, the force on it due to the electric field will be in the direction opposite to the field. Therefore, if the electron is on the 0-volt equipotential line, the force on it will not be zero. The magnitude, however, cannot be determined without additional information such as the value of the electric field or the distance between equipotential lines.
The correct answer would thus be (E) 'to the left, but its magnitude cannot be determined without knowing the distance between the lines'.