The concept of magnetic fields
Most people who studies physics hard tend to know the basic theory of magnetic fields, and just what they are exactly.
However, if you're not into physics but studying it because you need a good grade, then you might need to start off from the basics.
In physics, you always need to have a good understanding of basics, because you'll always need to refer back to the basics.
Remember, everything is derived from the basics!
Magnetism is the molecular property common to magnets. That's a dictionary definition.
Pretty damn hard to understand, and not clear at all. So what does this mean, in simplified terms?
Imagine that all molecules inside a magnet are bars with N / S poles. A magnet is a substance in which all of its molecules point to N or S, all in the same direction.
Kind of like this:
However, if you're not into physics but studying it because you need a good grade, then you might need to start off from the basics.
In physics, you always need to have a good understanding of basics, because you'll always need to refer back to the basics.
Remember, everything is derived from the basics!
Magnetism is the molecular property common to magnets. That's a dictionary definition.
Pretty damn hard to understand, and not clear at all. So what does this mean, in simplified terms?
Imagine that all molecules inside a magnet are bars with N / S poles. A magnet is a substance in which all of its molecules point to N or S, all in the same direction.
Kind of like this:
This is the general idea.
Now, a magnetic field is a field of magnetism. You can visualize it by thinking of a field that magnetism can influence.
Kinda like this: There is a field on either ends of a magnet. Outside that field, nothing happens.
But on the inside, the metallic objects are pulled towards the magnet (or the other way around if the magnet is lighter than the object).
The further the object from the edges of the field, the weaker it gets.
Now, a magnetic field is a field of magnetism. You can visualize it by thinking of a field that magnetism can influence.
Kinda like this: There is a field on either ends of a magnet. Outside that field, nothing happens.
But on the inside, the metallic objects are pulled towards the magnet (or the other way around if the magnet is lighter than the object).
The further the object from the edges of the field, the weaker it gets.
Important laws of Magnetism, and how they work
There is a number of 'Someone's Rule' in magnetism (and in the entire physics itself). The most famous is the Fleming's Left Hand rule, and the Right hand rule.
These two are maddeningly easy to get mixed up. Which is why you need to remember them correctly from the start.
Fleming's Left Hand Rule
This requires three fingers. This rule states that, like the diagram below, your thumb should point to the direction of the mechanical force on a wire, the pointer to the direction of the magnetic field, and the middle finger to the direction of the electric current.
This rule applies when a wire with a running electric current is put between a North and a South Pole.
These two are maddeningly easy to get mixed up. Which is why you need to remember them correctly from the start.
Fleming's Left Hand Rule
This requires three fingers. This rule states that, like the diagram below, your thumb should point to the direction of the mechanical force on a wire, the pointer to the direction of the magnetic field, and the middle finger to the direction of the electric current.
This rule applies when a wire with a running electric current is put between a North and a South Pole.
AC / DC - What's the difference?
When studying this section of physics, you'll probably get confused at least once because of the difference between AC and DC.
AC (alternating current) and DC (direct current) are both forms of electricity, but they are very different, even from their nature.
Basically, DC is a current you can see in a battery circuit: + to -. In a DC, the flow of electrons (which is electricity) is one-way.
AC (alternating current) and DC (direct current) are both forms of electricity, but they are very different, even from their nature.
Basically, DC is a current you can see in a battery circuit: + to -. In a DC, the flow of electrons (which is electricity) is one-way.
The picture above pretty much shows how electrons flow within a wire. Of course, the electrons and protons are much much smaller and denser.
There's nothing much more to say about DC. It's very straightforward.
Alternating Current, on the other hand, is much more trickier. Most books and websites only tell you that in AC, the voltage alternates between + and - quickly, the power system in US oscillating 60 times per second, and Europe 50 times per second.
In an alternating current, the flow of electric charge reverses direction every milisecond, its voltage value going from 0 to the peak, back to 0, to a negative peak, and back to 0 again, repeating the whole process again with no interruption. As long as there is a source of this phenomenon and something to conduct it, the wave will continuously move away from its source until either it's cut up, used up, or dies out because of the resistance of its conductor.
There's nothing much more to say about DC. It's very straightforward.
Alternating Current, on the other hand, is much more trickier. Most books and websites only tell you that in AC, the voltage alternates between + and - quickly, the power system in US oscillating 60 times per second, and Europe 50 times per second.
In an alternating current, the flow of electric charge reverses direction every milisecond, its voltage value going from 0 to the peak, back to 0, to a negative peak, and back to 0 again, repeating the whole process again with no interruption. As long as there is a source of this phenomenon and something to conduct it, the wave will continuously move away from its source until either it's cut up, used up, or dies out because of the resistance of its conductor.
The Power Loss Equation
P=VI=I^2R. Very hard to understand, but easy to apply. I can't really explain this in words.
Instead, I will post a youtube video that could help you much better than I can, in this case.
Instead, I will post a youtube video that could help you much better than I can, in this case.