Does a solenoid wrapped around a magnet meet resistance?

AI Thread Summary
When a solenoid is wrapped around a bar magnet and an electric current is passed through it, the interaction between the magnetic field and the current can cause movement. This principle is similar to how speakers operate, where the solenoid vibrates a cone based on the current's properties. The current itself may not encounter resistance from the magnetic field directly, as the force on charge carriers is perpendicular to their velocity. However, if the magnet moves against external forces like air resistance or friction, energy will be required from the power supply to perform that work. Understanding the nuances of resistance in this context may require further exploration of concepts like magnetoresistance and the Hall effect.
radaballer
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If a solenoid were wrapped around a bar magnet, and a charge were applied through the solenoid, would there be resistance?
 
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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.
 
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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).
 
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