Key ideas1 of 3
A current in a magnetic field experiences a force
Higher Tier: when a current-carrying wire is placed in a magnetic field, the wire and the magnet exert a force on each other. This is the motor effect: the magnetic field around the current interacts with the field of the magnet. In the diagram, the field between the poles points from north to south, towards the right. The dot represents conventional current coming out of the page. The resulting force on the wire points upwards. A non-zero motor-effect force is perpendicular to both the current and the magnetic field.
