Equipotential surfaces associated with an electric field that is increasing in magnitude along the positive Y-direction are

Step-by-step solution

The electric field is directed along the Y-axis. Equipotential surfaces are always perpendicular to the direction of the electric field. Since the electric field is along the Y-direction, the equipotential surfaces must be perpendicular to the Y-axis. Planes perpendicular to the Y-axis are parallel to the XZ-plane. The increasing magnitude of the electric field along the positive Y-direction implies that the spacing between consecutive equipotential surfaces decreases along this direction, but their orientation rem