Magnetism Unit Review

Source of all Magnetism: Moving Charges
What is a Magnetic Field?
- Area of influence created by moving charges, particles have to be moving PERPENDICULAR to said field to feel a force
A magnetized object has Magnetic Poles, North and South
Domains are groups of electrons that spin in the same direction
an object can become a magnet itself if its domains become aligned, usually from another magnet.
When a fara-magnetic object comes into a magnetic field, it increases the strength of said magnetic field.
Electromagnetism is a word to describe a magnetic field caused by electricity
Motors are made of Coils of wire and Magnets. When a current is run through the coils of wire, the resulting force vector caused by the magnetic field produced by the magnet puts a torque on the coil of wire. Note that current has to be alternated for this to work. For example when we made motors.
Magnetic Induction:
When you start with electricity to produce a magnetic field, it is called Magnetic Induction. This is done by running a current through wires. When starting with a magnetic field to produce electricity it is called Electric Induction. Both are at play in Transformers. Transformers are two different coils of wire that aren't touching each other but are next to each other. When current is changed in one of them, a magnetic field is induced. This change in magnetic field causes a current to flow in the second coil of wire. Transformers can be used to step voltage up or down by changing the number of loops, otherwise known as turns, in the coil. Double the turns= double the voltage. Note that this only works with alternating current because it is a change in magnetic field that produces a current.

Generators have similar design to motors, only its role is reversed. A generator will store mechanical energy as electrical energy.

Credit Cards:
Credit cards have a magnetic strip that include specifically coded and uniquely magnetic sectors. The Card reader has Coils of wire within it. When the magnetic strip is run through the card reader, a specific amount of current is created by the magnetic field from the coded sectors. This current is then translated by a computer into the original code (numbers).

Primary Voltage/Number of turns = Secondary voltage/ number of turns

power is always conserved, power in = power out
Voltage x Current= Voltage x Current
VI in = VI out
For long distances it is better to have less current in a power line due to the excess loss of energy to heat from high current. This loss of energy means that the power companies are not getting as much profit. Note, however, that the Voltage increases while the Current decreases.

Paperclips- you can turn a paperclip into a magnet by putting it in a magnetic field to realign its domains to match the magnetic field. When the magnet is removed, the paper clip will produce its own magnetic field.

Magnetic objects stick together because when their poles are in the same direction, their force vectors and in the same direction. This means that they will add together and the net force will be attractive.