magnet formulas


Field Due to an Infinite Straight Current Filament

This simple formula can be derived directly from Maxwell’s fourth equation, or Ampere’s Law.

Field due to an infinite straight wire

field due to an infinite straight wire

B is the magnetic field, in teslas. The direction of the field is tangent to a circle on a radius r (in meters) from the wire.

μo is the permeability constant (1.26x10-6 H/m)

i is the current in the wire, in amperes.


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