Can metal shavings orbit around a wire in a magnetic field-free room?

In summary, according to the speaker, metal filings would orbit around a wire in the same direction as the magnetic field lines if the current was held constant. If the current was changing, however, the filings would not reflect the changing field at every instant of time.
  • #1
Jules18
102
0
When a wire has current running through it, a magnetic field is created around it, right? And I've seen lots of diagrams of the magnetic field lines wrapped around a wire in a coil-like fashion.

So, hypothetically, imagine if there was a current running through a wire, and that wire was suspended in a room that was free of any gravity.
Would metal shavings orbit around that wire in the same direction as the magnetic field lines?
 
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  • #2
I think Iron filings would actually follow the magnetic flux rather than the current.
 
  • #3
Jules18 said:
When a wire has current running through it, a magnetic field is created around it, right? And I've seen lots of diagrams of the magnetic field lines wrapped around a wire in a coil-like fashion.

So, hypothetically, imagine if there was a current running through a wire, and that wire was suspended in a room that was free of any gravity.
Would metal shavings orbit around that wire in the same direction as the magnetic field lines?

No, that's how you'd expect a magnetic monopole to behave, if one actually existed. An iron filing (for example) would take on an induced dipole, which would simply align with the field rather than "flying" around the flux loops.
 
  • #4
If the current was held constant they would line up with the magnetic field lines, which would be closed circular loops around the wire. If the effect is to be noticeable this requires that the metal filings have some asymmetry. It's exactly the same effect produced when placing a permanent magnet in the vicinity of metal filings. Since every single filing gets magnetized they would attract each other, and therefore gather in lumps symmetrically placed around the wire. These could be very numerous resulting in a seemingly continuous circle. I think this might result in discrete rings forming, whose separation could be small. The net effect would be that you see contours of the field lines in the space not occupied by metal filings. It all depends on how the filings are spatially distributed before the magnetic field is applied.

If the current is changing I'm not entirely sure as of what exactly would happen. They wouldn't reflect the changing field at every instant of time, because the changing field induces a current in the filings, which in turns give rise to new magnetic field affecting the filings around it, and I can't tell the net effect. If the field is big enough it might overcome this induction effect and just move in accordance with the field changes.

Is there a simplifying principle I'm missing?
 

Related to Can metal shavings orbit around a wire in a magnetic field-free room?

1. What is a magnetic field?

A magnetic field is an invisible force created by the movement of electrically charged particles. It is responsible for the attraction or repulsion of magnetic materials.

2. What is a hypothetical magnetic field?

A hypothetical magnetic field is a theoretical concept that is used to explain the behavior of charged particles in the absence of an actual magnetic field. It is often used in scientific models and thought experiments.

3. Is there any evidence for a hypothetical magnetic field?

There is currently no direct evidence for a hypothetical magnetic field. However, many scientific theories and models rely on the existence of a hypothetical magnetic field to explain observed phenomena.

4. How is a hypothetical magnetic field different from a real magnetic field?

A hypothetical magnetic field is a purely theoretical construct, whereas a real magnetic field can be measured and observed in the natural world. Additionally, a hypothetical magnetic field does not have a physical source, whereas a real magnetic field is generated by moving electric charges.

5. What are some applications of a hypothetical magnetic field?

A hypothetical magnetic field is used in a wide range of scientific fields, including physics, chemistry, and materials science. It is often used to study the behavior of particles in extreme conditions, such as in the early universe or inside black holes. It also plays a crucial role in the development of technologies such as MRI machines and particle accelerators.

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