20.2.1—A force might act on a current-carrying conductor placed in a magnetic field

A current-carrying conductor experiences magnetic force when its current has a component perpendicular to an external magnetic field.

Reverse current or field direction to reverse force. Parallel current and field produce no force in the ideal straight-wire model.

A wire between magnet poles deflects when current flows, forming the basis of a simple motor.

The force is not caused by current alone; it requires interaction with an external magnetic field.