Why the direction of the current is determined by which way you move the magnet

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Discussion Overview

The discussion revolves around understanding why the direction of the electric current induced in a coil is determined by the direction in which a magnet is moved through it. Participants explore concepts related to Faraday's law, Lenz's law, and the behavior of electrons in magnetic fields, with a focus on theoretical and conceptual explanations.

Discussion Character

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

Main Points Raised

  • Some participants suggest that the negative sign in Faraday's law is crucial for understanding the direction of the induced current.
  • One participant requests a deeper explanation of the negative sign's significance in the context of the law.
  • Another participant shares a link to a problem they worked out related to coils, indicating a desire for practical examples.
  • Some participants express frustration over the reliance on formulas and graphs, preferring textual explanations instead.
  • A participant describes a conceptual model where electrons move to create a magnetic field that opposes the applied magnetic field, suggesting that the direction of electron movement is influenced by the magnetic field's direction.
  • One participant references Lenz's law and conservation of energy to explain why the induced current must oppose changes in magnetic flux.

Areas of Agreement / Disagreement

Participants express differing preferences for explanations, with some favoring mathematical formulations while others seek conceptual understanding. There is no consensus on the best approach to explain the phenomenon.

Contextual Notes

Some participants indicate a lack of understanding of the basics, which may limit the effectiveness of more technical explanations. The discussion includes references to external resources and prior threads, suggesting a broader context for the topic.

Who May Find This Useful

This discussion may be useful for individuals interested in electromagnetism, particularly those seeking to understand the principles behind induced current and magnetic fields, as well as those who prefer conceptual over mathematical explanations.

scientist91
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why the direction of the current is determined by which way you move the magnet through the coil?
 
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because there is a negative sign in faraday's law
 
ice109 said:
because there is a negative sign in faraday's law
explain deeper please. Thank you.
 
i almost started to use swear language.
 
so what the fsck do you want?

hm?

there are the graphs, showing the current vs time.
and formulas are neccesary.
what do you want to undertand, if you are not familiar with the basics?
 
mcstar said:
so what the fsck do you want?

hm?

there are the graphs, showing the current vs time.
and formulas are neccesary.
what do you want to undertand, if you are not familiar with the basics?
I am interested about the electrons. I don't need equations.
 
In my imagination (without any formulas or graphs), thing can be like this. Electrons move and create magnetic field. The direction of the field is always perpendicular to the direction of the electron, and let say to the right. It is something like when you run, you hold a board which is 45 degrees off the running derection and facing to the right. then you always create wind to your right hand.
When you have a moving magnetic field, the electron would move so that it creates a M. fiedl that is opposite to the applying magnetic field. And so its moving direction depends on the direction of the field.
 
  • #10
because the current has to oppose the change in flux
because of conservation of energy and i quote from my intro physics book

"Think what would happen if Lenz's law were turned the other way around, that is, if the induced current acted to aid the change that produced it. You would then need to push a stationary magnet only slightly to get it moving, and the action would be self perpetuating..."

and mcstar's explanation is very good.
 

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