Wire coil with current creates magnet with north and south poles {magnetic dipole}|.
field
Magnetic-field direction relates to current direction. By right hand rule, if positive current points in right-hand finger direction, magnetic-field direction points in thumb direction for north magnetic pole, and the opposite direction is south magnetic pole.
force
Like magnetic poles repel. Opposite magnetic poles attract. Force between magnetic poles equals space magnetic permeability k' times one magnetic-pole strength P times other magnetic-pole strength p, divided by distance r between poles: F = k' * P * p / r.
pole
Current i times path length L is pole strength p: p = i*L. Pole strength p equals charge q times velocity v: p = q*v.
infinitesimal
Infinitesimal wire loops can have unit current {elementary magnet}, to make idealized unit dipoles.
Physical Sciences>Physics>Electromagnetism>Magnetism>Induction
5-Physics-Electromagnetism-Magnetism-Induction
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Date Modified: 2022.0224