SUBJECT: The Line of Charge
DESCRIPTION: This simulation illustrates the electric field generated by a line of charge, and shows how, by the principle of superposition, a continuous charge distribution can be thought of as the sum of many discrete charge elements. Each element generates its own field, described by Coulomb's Law (and represented here by the small vectors attached to the observation point), which, when added to the contribution from all the other elements, results in the total field of the ring (given by the large resultant vector, and by the large two dimensional field map). By moving the observation point around with the arrow keys, changes in field magnitude and direction can be observed at different positions relative to the line.
Note that if this were truly an "infinite line" of charge, the components of the field in the direction of the line would cancel each other out. The resultant field would thus be described only by the contributions perpendicular to the axis of the line.
VISUALIZATION: Fullscreen Version