Why won't a magnet exert a force on a stationary charged particle

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Discussion Overview

The discussion centers around the differences between electric and magnetic fields, particularly why a magnetic field from a permanent magnet does not exert a force on a stationary charged particle, while a static electric field does. The scope includes conceptual clarifications and technical explanations related to electromagnetism.

Discussion Character

  • Conceptual clarification
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions why a static electric field can exert a force on a stationary charged particle, while a magnetic field from a permanent magnet cannot, suggesting that the magnetic field should generate electric field lines due to charge polarization.
  • Another participant asserts that permanent magnets do not create closed electric field lines and that only changing magnetic fields can generate electric fields.
  • A participant challenges the assertion regarding electromagnets, asking if the current flowing through the wire generates an electric field.
  • It is noted that for an electromagnet, there are no closed electric field lines outside of the wire coils, similar to the behavior of permanent magnets.
  • One participant mentions that electric current is a flow of charges but maintains a net charge of zero, indicating that electrons are not added to the wires but are instead moved through the coils.
  • Another participant draws an analogy between the current in a superconducting loop and a permanent magnet, suggesting that both do not have an electric field around them.
  • It is pointed out that a resistive wire does set up an electric field due to voltage drop, contrasting with the behavior of superconducting wires.
  • One participant states that when an electromotive force (emf) is induced in a coil, it generates a dynamic magnetic field that can cause moving particles to interact with stationary particles.
  • A later reply expresses confusion regarding the explanation provided about induced emf and its effects on particle movement.

Areas of Agreement / Disagreement

Participants express differing views on the nature of electric fields generated by permanent magnets and electromagnets, with no consensus reached on the implications of these fields for stationary charged particles.

Contextual Notes

Some statements rely on specific definitions of electric and magnetic fields, and the discussion includes assumptions about the behavior of currents in different types of wires, which may not be universally accepted.

d4rr3n
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Why is it that a static electric field will exert a force on a stationary charged particle but a magnetic field from a permanent magnet will not?

I am somewhat confused by this because the magnetic field in a permanent magnet is the result of spin charge polarisation which must generate closed electric field lines which wraparound the bar magnet at right angles to the magnetic field.

If we think about an electromagnetic we have electrons flowing through a wire so there is charge which must generate electric field lines again at right angles to the magnetic field. why is it these electric field lines exert no force on a stationary charged particle?

What's different about the nature of these electric fields that one will exert a force on a stationary charged particle but the other wont?
 
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No, permanent magnets do not create closed electric field lines that wrap around the magnet. A changing magnetic field generates an electric field, but a static magnetic field (of a magnet) will not generate an electric field.
 
So the current flowing through the wire of an electromagnet generates no electric field?
 
Khashishi answered for permanent magnets. For an electromagnet, there will be no closed electric field lines outside of the wire coils. It is essentially the same if you are viewing it completely outside of the material.

Remember, electric current is a flow of electric charges, but the net charge is still 0. Electrons aren't added to the wires, just pulled through the coils.
 
d4rr3n said:
So the current flowing through the wire of an electromagnet generates no electric field?
A closer analogy is the current flowing through a superconducting loop. Those indeed generate no electric field.
 
But a wire has resistance hence there is an electric field set up because there is a voltage drop ie;

Vwire = Iwire X Rwire
 
That is precisely what makes a superconducting wire a better analogy for a permanent magnet than a resistive wire. Neither a superconducting wire nor a permanent magnet have an electric field around the current loop.

Of course, it is just an analogy, so it isn't perfect, but it does clearly show that you can have current without E fields.
 
Yes, When an emf is induced in the coil than a dynamic field is generate it will create a magnetic field that will cause to generate moving particle and these particles attract stationary particle and they will start to moving in the magnetic field.
 
Leesa Johnson said:
Yes, When an emf is induced in the coil than a dynamic field is generate it will create a magnetic field that will cause to generate moving particle and these particles attract stationary particle and they will start to moving in the magnetic field.

I'm sorry, Leesa, but I'm having trouble understanding what you've said here.
 

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