What is Magnetism?
Magnetism is the force that is exerted by magnets which attracts other objects with opposite magnetic poles. Another way to put it is that magnetism is the movement between charged objects. When something with one charge moves towards another object with the opposite charge that is magnetism. It can be an electric current. I think the best way to describe magnetism though is the moving charges that cause things to become magnetic.
What are Magnetic poles?
A magnetic pole is one of the two ends of a magnet. It will either be the north pole or the south pole. On the outside of the magnet the electrical current flows from the north to the south pole and the inside of the current flows from south to north. The magnetic field is strongest in these two regions. The electromagnetic interactions cause the opposite ends to attract and the like ends to repel each other. The earths north pole is not actually the north pole and the earths south pole is not actually the south pole. The names were switched because the north end of the compass with points north would be attracted to the south pole of the earth. This is the same with the south pole. When the compass points south it is really the south pole of the magnetic which is attracted to the north pole of the earth. The names are just flipped.
FARADAY'S LAW: induced voltage in a coil is proportional to product of its number of loops the cross sectional area of each loo[ and rate at which magnetic field changes within the loops
What is electromagnetism?
Electromagnetism is a current carrying coil of wire. Its strength is increased by increasing the current. Sometimes the current is increased by adding iron. (pretty much what I already talked about in the previous sections)
Ways the voltage can be induced:
1.) change magnetic field
2.)move magnet / move coil
3.) change current in nearby coil
A few other important terms:
Magnetic force: the force due to the motion of the charged particles
Magnetic fields: the space around the magnet...filings align with magnetic field lines that spread out from one pole to the other
Magnetic domains: a cluster of aligned atoms
Forces on charged particles in electric fields/ Motors
What is a motor?
In order to make a motor you must have the following:
Battery: used to supply voltage and current
Coil of wire: provides a pathway for the current to flow through
Paperclip: the paperclip connects wire to the battery and completes the circuit
Magnet: makes the loop turn because it makes a magnetic field
The force is created because the wire is perpendicular to the magnetic so the upward current puts a force on the charges causing them to move in one direction. They change their direction because of the magnetic field. We had to coil the ends of the wire around the paperclip so it can connect to cause current to flow. There are two forces. One on the bottom and one on the top going in opposite directions causing the spin.
Electromagnetic induction and common applications
Electromagnetic induction is an electric force which is caused by the magnetic field around a charged object. The only way electromagnetic induction can occur is if the magnetic field is changing. The magnetic field can be changed by moving the magnets, moving the coils, or changing the current in the nearby coil. This induction can not occur if the magnetic field is staying the same. This is why DC does not work, and AC must be the only way to create induction because the force is alternating.
One common application where electromagnetic induction is seen is in a generator. The way a generator works is that the mechanical energy is turned into electrical energy. Once the generator has a source of mechanical energy the current will be transformed into electrical energy.
Transformers and energy transfer from power company
The transformer is used in order to make good use of all of the energy transferred from a power company. They don't want to waste the energy because then they would use money. Sometimes the energy isn't sufficiently used and it is transferred in other ways such as heat. In order to stop this from happening a transformer is used.
The transfer does this by increasing the voltage which then will lower the current and thus less power is lost and the energy is used sufficiently.
There are two different sides of a transformer the primary and the secondary.
PRIMARY: input
SECONDARY: output
The equation to prove this is Vp/Tp=Vs/Ts
The voltage of the primary is equal to the voltage of secondary and
the turns of the primary equals the turns of secondary
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