Motor Effect

• The motor effect is the idea that a current carrying wire in the presence of a magnetic field will experience a force.
• The direction of the force and its strength can be determined using Fleming's left-hand rule.
• A current carrying wire will produce its own magnetic field, which means that if a wire is placed between the north and south poles of two magnets, the two magnetic fields will interact, resulting in a force on the wire.
• The full force on the wire is felt when it is at exactly 90 degrees to the magnetic field.
• If the wire is at a slight angle to the magnetic field, it will feel slightly less force.
• If the wire is running in the same direction as the field, it will feel no force.
• To find the direction of the force, you need to know the direction of the magnetic field and the direction of the current in the wire.
• Fleming's left-hand rule involves taking your left hand and pointing your thumb up, your first finger forwards and your second finger out to the side.
• The first finger of Fleming's left-hand rule represents the direction of the magnetic field, pointing from the north to the south pole.
• The second finger of Fleming's left-hand rule represents the direction of the current in the wire.
• The direction of the force felt by the wire can be determined by the position of your thumb.
• The strength of the force can be calculated using the equation F = B * I * L, where F stands for force, B stands for magnetic flux density, L stands for length and I stands for current.
• The magnetic flux density, B, is measured in teslas and is a measure of the strength of the magnetic field.
• The length of the wire, l, is also a factor in the equation F = B * I * L.
• If a 10 centimeter piece of wire with a 5 amp current flowing through it is placed at 90 degrees into a magnetic field that has a magnetic flux density of 0.4 teslas, it will experience a force of 0.2 newtons.
• This shows how a magnetic field of a wire will interfere if placed with a magnet eg in the motor effect.

  
• Fleming's left hand rule: thuMb = Motion (direction of force), First finger= field, seCond finger= direction of Current