I am currently busy with some magnetism and quite shockingly (to me at least) I haven't yet read anything about the difference between the north pole and the south pole of a magnet. Before I started with magnetism I learned electricity, here there 2 opposite charges: negative charges (electrons) and positive charges (protons). Although I know for the people on this forum, that is very rudimentary, I at least find at a satisfactory explanation; different particles have different charges; a positive or a negative one. With magnetism I haven't stumbled across this yet.
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My teacher told me you can't say there is a positive and negative 'magnetic charge' (I don't know how to call it); but why?
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Also, what causes the difference between the 2?
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And, now that I'm thinking about it; are there actually magnets with only a north pole or a south pole (if not, why are the 2 so fundamentally connected that you can't have one without the other)?
Best Answer
Your teacher's statement that you can't talk about positive and negative magnetic charge is ... difficult.
You see, there have been no observations of any magnetic charges (which are called "magntic monopoles"), but a lot of theorists favor the existence of such criters because
If there are magnetic monopoles then they would comes in positive and negative varieties, and even though they are not monopoles the difference between the poles of a magnetic is very much the same as the difference between positive and negative electric charges.
To illustrate what I mean by the difference being like that between charge polarities, consider that electric field lines are seen as coming "out" of positive charges and going "in" to negative charges. Likewise--if we don't look inside the magnet--magnetic field lines are drawn going "out" from the north pole and "in" to the south pole. (Looking inside the magnet the situation is reverse, because in the absence of monopoles all magnetic field lines are loops, but I don't want to get into that.)