# Homework Help: North and South Poles

1. Jan 28, 2006

### MPonte

What is the difference between the north pole and the south pole of a magnet?

2. Jan 28, 2006

### Tide

One way of thinking about it is that magnetic field lines start at one pole and end at the other. In other words, the direction of the field at each of the poles is the reverse of the other relative to the surface. Ulitmately, the magnetic field is the result of an electrical current (you can think of the magnetic moment of an atom or nucleus as arising from a spinning electrical charge, i.e. a current) with the direction of the field being related to the direction of the current. Clearly, the direction of the magnetic field produced by a current depends on position relative to the current.

3. Jan 28, 2006

### MPonte

Thank you very much.
But due to my weak english understanding your explanation raise on me some doubts.

"One way of thinking about it is that magnetic field lines start at one pole and end at the other. In other words, the direction of the field at each of the poles is the reverse of the other relative to the surface."

Which surface?

"you can think of the magnetic moment of an atom or nucleus as arising from a spinning electrical charge, i.e. a current"

What is the magnetic moment?

"Clearly, the direction of the magnetic field produced by a current depends on position relative to the current."

Could you try to explain it better?

4. Jan 28, 2006

### Tide

The surface of the poles on the magnet you asked about.

That is the magnetic field produced by an atom or nucleus. It is the sum of those magnetic moments that are responsible for the magnetism in the magnet you asked about.

Look up "Ampere's Law" and "Biot-Savart" in your textbook. :)

5. Jan 28, 2006

### MPonte

My textbook does not have any information about that. Unfortunely, the portuguese high school physics teaching is very poor. That's my opinion. But I will google for Ampere's Law and Biot-Savart. Thank you very much for your help.

6. Jan 28, 2006

### Ouabache

For a little visual to go along with Tide's discussion. see this reference

7. Jan 29, 2006

### PPonte

Thank you Ouabache. This explication was very clear and simple. It helped a good deal.

Last edited by a moderator: Jan 29, 2006