aps01 image01 physics image Rings of Current

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Rings of Current

See more from "Visualizing Physics: Technology-Enabled      Active Learning at MIT." Find more visual aids for electromagnetism.

The permanent magnet is suspended above a ring of current in this visualization. The magnet is oriented such that its north pole faces downwards, while the current in the ring flows counter-clockwise. A ring with current flowing through it generates a magnetic field that looks roughly like the field of a magnet — when the current is flowing counter-clockwise, it looks like a magnet with its north pole facing upwards. The resulting pressure in the field between the two objects causes the magnet to be repelled, feeling a force upwards that allows it to be levitated above the ring. The image shows selected fieldlines colorized and rotated about the vertical axis.