Electromagnetism is caused by the magnetic fields around electric currents. The fields can cause forces with other nearby magnets and these forces can be used to make motors spin.
The force on a given length of wire in a magnetic fieldArea surrounding a magnet that can exert a force on magnetic materials. increases when:
the current in the wire increases
the strength of the magnetic field increases
For any given combination of current and magnetic field strength, the force is greatest when the direction of the current is 90掳 to the direction of the magnetic field. There is no motor effectThe effect where a force is exerted on a wire carrying a current in a magnetic field. force if the current and magnetic field are parallel to each other.
The direction of a motor effect force can be found using Fleming鈥檚 left-hand rule.
Hold your thumb, forefinger and second finger at right angles to each other:
the forefinger is lined up with magnetic field lines pointing from north to south
the second finger is lined up with the current pointing from positive to negative
the thumb shows the direction of the motor effect force on the conductor carrying the current
In which direction will this wire feel a force?
With forefinger (magnetic field) pointing left to right, and second finger (current) pointing down, your left thumb (force) will point towards you. This is the direction in which the force acts.