Force on a current-carrying wire
(E7.3.1) E7.3 · Force on a Current-Carrying Wire →The force on a straight length of current-carrying wire in a uniform field, with L a vector along the wire in the direction of current flow.
| force on the wire | N | |
| current | A | |
| length vector along the wire | m | |
| magnetic field | T |
A straight wire segment in a uniform field, or the straight-line vector between endpoints of a curved one.
The vector L represents a straight wire segment — for a curved wire, only the straight-line vector between endpoints is used, which is valid only in a uniform field.
Sum the magnetic force qv×B over every charge carrier in the wire segment, using I = nqvA to replace the microscopic quantities with the measurable current:
L is a vector along the current's direction with magnitude equal to the wire's length — for a wire that curves through a uniform field, only the straight-line vector between its endpoints matters.