EMC Question of the Week: November 2, 2026
The field lines between the two parallel wires illustrated in the figure are
- electric field lines
- magnetic field lines
- magnetic flux lines
- equipotential lines
Answer
The best answer is “a.” Electric field lines start on positive charge and terminate on negative charge. In electrically small structures, they start on conductors with higher voltage and terminate on conductors with a lower voltage. Lines of magnetic flux cannot start and stop, so they always form closed loops. In environments without magnetic materials, the magnetic field lines look identical to the magnetic flux lines. In this example, they would encircle the current-carrying conductors.
Equipotential lines are perpendicular to the electric field lines. In homogeneous materials, they would follow the same path as the magnetic field lines. Also, equipotential lines are not vector fields. Electric potential (voltage) is a scalar quantity and does not have a direction, therefore equipotential lines would never be drawn with arrows.
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