Equipotential surfaces are imaginary surfaces in which all points have the same electric potential. These surfaces are formed by connecting points in space where the electric potential is equal. The concept of equipotential surfaces is crucial in understanding the behavior of electric fields.

When visualizing equipotential surfaces, it is important to note that the electric field lines are always perpendicular to these surfaces. This means that as we move from one equipotential surface to another, the electric field lines are crossed at right angles. The electric field lines are closer together in regions with a strong electric field and farther apart in regions with a weaker field.

To illustrate this concept, let's consider a positive point charge. The equipotential surfaces around the charge are concentric spheres with the charge at the center. Since the electric potential is the same at all points on a given sphere, we can visualize these spheres as layers of constant electric potential.