Do magnetic poles of an object have to be perpendicular to the object's surface?

In summary, the poles of a magnet can be located anywhere on the magnet, depending on how you magnetize it.
  • #1
Terresquall
7
0
Topic. If I have an iron shaped like a bar magnet placed flat on the floor, can the poles of the magnet be pointing anywhere else other than 90 degrees and 180 degrees?
 
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  • #2
They can. But I would expect that the field you can get with unusual orientations is a bit weaker, as the magnetic field gets an odd shape.
 
  • #3
The poles don't point. They have no direction. Just a location.
 
  • #4
Magnetic flux lines are always normal to the surface at a pole.
 
  • #5
The poles can be located anywhere on an object depending on how you magnetize it. By the way, the concept of macroscopic "poles" is a loose conceptual entity that helps visualize thing. There is no exact pole location - a single point in space - where a little physical thing called a pole sits. Rather, a material can have a magnetization throughout its extent. If the magnetization is fairly uniform and the object's shape is fairly simple, then it looks like all the field lines are created by two poles on opposite sides of the object.

For example, four loops of current-carrying wire produce the magnetic field shown below. Where exactly would you say is the location of the poles?

220px-VFPt_quadrupole_coils_1.svg.png
 
  • #6
A "magnetic dipole" is, as described above, a vague and ambiguous term. Indeed, magnetic dipoles do not even exist in nature (div(B) = 0, always). In a general sense, though, all magnetic field lines are not always normal to the current-carrying surface.
This follows directly from the Biot-Savart law, in the general case of a surface current:

B(r) = [itex]\frac{\mu}{4\pi}[/itex] [itex]\int[/itex] [itex]\frac{K(\acute{r}) χ \hat{r}}{r^2}[/itex]d[itex]\hat{\tau}[/itex]

where K([itex]\acute{r}[/itex]) is the surface current density,
and [itex]\hat{r}[/itex] is the vector extending from the source to the point r

We note that the direction of the magnetic field will be given by the cross product between a vector pointing in the direction of the current and a vector pointing towards the point. Ergo, the magnetic field lines must always be perpendicular to the direction of current, but may not be perpendicular to the surface itself.
In your particular case, the field lines will always be perpendicular to the outer edges ("dipoles") of the bar.
Hope this helped. :3
 
  • #7
Thanks to everyone who's helped. My question has been adequately answered :)
 

Related to Do magnetic poles of an object have to be perpendicular to the object's surface?

1. Do all objects have magnetic poles?

Yes, all objects have magnetic poles. Every atom contains electrons, which have a magnetic field and therefore contribute to the overall magnetic field of an object.

2. Can an object have more than two magnetic poles?

No, an object can only have two magnetic poles - a north pole and a south pole. This is due to the fundamental nature of magnetism, which is based on the alignment of electron spin within atoms.

3. Can the magnetic poles of an object change?

Yes, the magnetic poles of an object can change. This is known as magnetic remanence and can occur when an object is exposed to a strong external magnetic field or is heated to a certain temperature.

4. Does the orientation of an object's magnetic poles affect its magnetic field strength?

Yes, the orientation of an object's magnetic poles can affect its magnetic field strength. The strongest magnetic field is generated when the magnetic poles are perpendicular to the surface of the object.

5. Are the magnetic poles of an object always perpendicular to its surface?

No, the magnetic poles of an object are not always perpendicular to its surface. The orientation of the magnetic poles can vary depending on the object's shape and composition.

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