Lab Notes - Electric Field and Equipotential Lines- Physics 2426 Theory Two points in an electric field have a difference of potential (voltage) if work is required to carry a charge from one point to the other. It is possible to find a large number of points in an electric field, all of which have the same potential. If a line is drawn that it includes all such points, the line is known as an equipotential line. A test charge may be moved along an equipotential line without doing any work. Since no work is done in moving a charge along an equipotential line it follows that there can be no component of the electric filed along an equipotential line. Thus the electric field lines must be everywhere perpendicular to the equipotential surface. Objective: Analyze the electric field by measuring equipotential lines (lines of equal voltage) and plotting the electric field lines generated by different electrical configurations