Definition
A wire carrying a current creates a magnetic field.
This can interact with another magnetic field, causing a force that pushes the wire at right angles.
This is called the motor effect.
There is a force at right angles to the current and the magnetic field
The size of the force is increased if:
- the current in the wire increases;
- the strength of the magnetic field increases;
- the length of wire inside the magnetic field is increased.
The force is always greatest when the direction of the current is 90掳 to the direction of the magnetic field.
The direction of the force is always at 90掳 or perpendicular to both the direction of the current and the direction of the magnetic field.
There is no motor effect force if the current and magnetic field are parallel to each other.