walters said:
I'm still confussed on how the magnetic field creates opposition
Lenz's law states that a current will create a magnetic field (actually, it states much more, but the basic gist is that current is always accompanied by a magnetic field).
How does that create opposition?
Lets think about an ideal coil (no resistance). An ideal coil is basically a short. If I connect the coil to a voltage source the current will be infinite because there is no resistance. However, this is not true immediately because the coil has no magnetic field surrounding it to begin with. So, in passing the current through the coil I establish the magnetic field. A magnetic field can attract or repel objects which are also magnetic. So, therefore a magnetic field has the potential to do work and contains energy. To establish a magnetic field, I must put energy into it. To make a magnetic field stronger, I must put more energy into it, to make it weaker, I must take some away. The only method I have of adding or removing energy is adjusting my current through the coil.
Let's assume I connect this coil to an ideal voltage source. To begin with, I have no magnetic field. Since I have no magnetic field, I have no current BUT I am applying a voltage which is trying to force current into the coil. So, though I have zero current, the voltage source begins to push some current through the coil. This current begins to establish a magnetic field (remember that requires energy which is the same as voltage times current times time). So, my current increases gradually as I add energy to the magnetic field equal to the voltage times the current over time. The fact is, to establish the field, I must supply energy. Since I am supplying energy there is an opposition to current flow.
walters said:
and how a capacitors electric static field creates opposition
This is very similar, except instead of adding energy to a magnetic field I am adding energy to an electric field.
There is a more visible way to think of this one however. Electrons try to repel one another. But if I connect a capacitor to an ideal current source, I am supplying electrons to one plate (and removing them from the other plate). Since the electrons repel one another, pushing them close together requires work. So, I am storing work into the capacitor and this causes the opposition to current flow.