Final answer:
To find where the electric potential is zero, we look for points on the same equipotential line as the ground or reference point set to zero volts. Without a specific setup, we rely on general principles stating that points along the same equipotential line as the zero potential reference have zero electric potential.
Step-by-step explanation:
The student is asking about the electric potential at various points in an electric field. To determine the positions where the electric potential is zero, we must consider the concept of equipotential lines or surfaces, which are areas in an electric field where the electric potential is the same.
The ground potential is usually taken as zero, and it is used as a reference point. Therefore, if a point is on the same equipotential line as the ground, it will have zero electric potential. Moreover, if the lowest potential plate is set to zero volts, the points along the line directly adjacent to it would also have a potential of zero volts.
The specific setup was not detailed in the provided information, but based on general principles, one would measure potentials relative to the ground or zero potential reference, and points on the same equipotential line as the zero reference would have zero potential.