The discussion revolves around the mechanisms that cause electrons to move in a conductor when a magnet is moved within a closed circular loop. Participants explore concepts related to electromagnetic induction, the role of induced electric fields, and the conservation of energy in this context.
Participants generally agree on the role of induced electric fields and the opposition to changes in magnetic flux, but there remains uncertainty and debate regarding the underlying reasons for these phenomena and the nature of electric fields.
Some discussions involve assumptions about the nature of electric fields and the role of energy in the system, which are not fully resolved. The conversation reflects varying levels of understanding and interpretations of electromagnetic principles.
Doc Al said:What moves the electons is the induced electric field created by the moving magnetic field. The current is always induced in a direction to oppose any change in the magnetic flux through the loop. As you move the pole of a magnet towards the loop, you are increasing the flux in the loop--the electrons will move to reduce it.
See: http://hyperphysics.phy-astr.gsu.edu/hbase/electric/farlaw.html"
nanoWatt said:This question made me think. Do only electrons produce an electric field, and what would the electric field be composed of? I am assuming the electric field is continuous with no gaps. I don't think it's solid electrons. I guess it's just some form of energy.
Doc Al said:It's a consequence of the conservation of energy. Read those links.
It takes energy to get a current flowing. That energy comes from the work you have to do in pushing the magnet into the loop. (The induced current exerts a force on the magnet that opposes its motion--you have to push the magnet, which takes energy.)Physicsissuef said:Conservation of energy of the electrons or?
And when I push the magnet back, why the electrons are going in same direction of the magnetic field, so they want to connect with it?Doc Al said:It takes energy to get a current flowing. That energy comes from the work you have to do in pushing the magnet into the loop. (The induced current exerts a force on the magnet that opposes its motion--you have to push the magnet, which takes energy.)
The induced current always resists any change in flux. When you pull the magnet back you are acting to decrease the flux, so the current moves so as to increase it. (Again, this takes energy. You have to pull the magnet.)Physicsissuef said:And when I push the magnet back, why the electrons are going in same direction of the magnetic field, so they want to connect with it?
Ok, I understand that. But why it wants to increase it?Doc Al said:The induced current always resists any change in flux. When you pull the magnet back you are acting to decrease the flux, so the current moves so as to increase it. (Again, this takes energy. You have to pull the magnet.)