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MIT Physics 8.02 - Electricity & Magnetism

SECTION : Calculating Magnetic Fields     

SUBJECT: The Ring of Current  
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This simulation illustrates the magnetic field generated by a ring of current, and shows how, by the principle of superposition, a continuous current distribution can be thought of as the sum of many discrete current elements (in this case, thirty). Each element generates its own field, described by the Biot-Savart 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 ring.

Note that along the axis of the ring, the perpendicular component of each element's field is cancelled out by the corresponding element directly opposite it on the other side of the ring. The resultant field is thus described only by the contributions along that axis.



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