Does a solenoid wrapped around a magnet meet resistance?

Click For Summary

Discussion Overview

The discussion revolves around the interaction between a solenoid wrapped around a bar magnet and the concept of resistance when an electric charge is applied through the solenoid. Participants explore the principles involved, including the mechanics of speakers and the effects of magnetic fields on charge carriers.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants question the phrasing of "applying a charge," suggesting that it may be more accurate to refer to passing an electric current through the solenoid.
  • One participant asserts that the interaction of the magnetic field with the solenoid is similar to the principle behind how speakers operate, where either the solenoid or the magnet may move depending on their anchoring.
  • There is uncertainty about whether the current will encounter resistance as it moves the magnet, with one participant noting that the force on charge carriers due to the magnetic field is perpendicular to their velocity, which may not slow them down directly.
  • Another participant introduces the concept of the Hall effect, suggesting that charge carriers may be pushed to one side of the wire, potentially leading to added friction.
  • A reference to magnetoresistance is provided as a related concept that may pertain to the discussion.
  • Participants discuss the need to clarify what is meant by "resistance," particularly in the context of the magnet doing work against external forces like air resistance or friction.

Areas of Agreement / Disagreement

Participants express differing views on the nature of resistance in this scenario, and there is no consensus on whether the current will encounter resistance or how to define it in this context.

Contextual Notes

Participants highlight the importance of clarifying definitions and assumptions regarding resistance and the forces at play in the system, which remain unresolved.

radaballer
Messages
86
Reaction score
0
If a solenoid were wrapped around a bar magnet, and a charge were applied through the solenoid, would there be resistance?
 
Physics news on Phys.org
I don't think you can 'apply a charge'. Do you mean that a electric current is passed through the solenoid?
 
radaballer said:
If a solenoid were wrapped around a bar magnet, and a charge were applied through the solenoid, would there be resistance?

This is exactly the principle behind how speakers work. Either the solenoid or the magnet would be caused to move (depending on which is anchored more sturdily) due to the interaction of the resulting magnetic field. In a speaker, of course, it is the solenoid that moves and vibrates a cone with varying effects depending on the properties of the current passed through it.
 
  • Like
Likes   Reactions: radaballer
Sturk200 said:
This is exactly the principle behind how speakers work. Either the solenoid or the magnet would be caused to move (depending on which is anchored more sturdily) due to the interaction of the resulting magnetic field. In a speaker, of course, it is the solenoid that moves and vibrates a cone with varying effects depending on the properties of the current passed through it.
Ok, will the current encounter resistance as it moves the magnet?
 
Look at it from the point of view of conservation of energy.
 
radaballer said:
Ok, will the current encounter resistance as it moves the magnet?

I'm not totally sure. I do know, however, that whatever force the charge carriers feel as a consequence of the magnetic field will be in a direction perpendicular to their velocity, so they will not be slowed down by the magnetic field itself. But they will be pushed to one side of the wire (see the Hall effect on wiki). It seems conceivable that there might be some added friction or something like that if all the charges are pushed into the wall of the wire, but I can't say anything definite about that.
 
radaballer said:
Ok, will the current encounter resistance as it moves the magnet?

Perhaps we should ask what do you mean by "resistance" in this case?

If you want the magnet to do any work (including moving itself against air resistance or friction) then the energy to do that will have to come from somewhere (eg the power supply to the solenoid).
 

Similar threads

High School Magnet inside a solenoid with current
  • · Replies 7 ·
Replies
7
Views
2K
Undergrad Can nested solenoids trap particles?
  • · Replies 12 ·
Replies
12
Views
1K
Undergrad Question about Activating Solenoids that are facing each other
  • · Replies 1 ·
Replies
1
Views
2K
Insights How to Model a Magnet Falling Through a Solenoid
  • · Replies 10 ·
Replies
10
Views
3K
Undergrad Magnetic field at a point along the solenoid's axis but outside the solenoid
  • · Replies 5 ·
Replies
5
Views
2K
Undergrad Calculation for proportional mechanical solenoid Force
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad When is Ampere's Law applicable in different scenarios?
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad How can magnetic fields contain energy?
  • · Replies 17 ·
Replies
17
Views
3K
Undergrad Producing enough force with a Solenoid
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Why is an iron cover needed for a solenoid?
  • · Replies 4 ·
Replies
4
Views
2K