What causes potential difference in the conductor?

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SUMMARY

The discussion centers on the causes of potential difference in conductors, specifically how changing magnetic flux induces electromotive force (EMF). Participants reference Faraday's Law, which states that a changing magnetic field generates an electric field, leading to a potential difference. The conversation highlights the relationship between electric and magnetic fields, emphasizing that the induced electric field affects free electrons in conductors, resulting in current flow. Understanding these principles is essential for grasping electromagnetic induction.

PREREQUISITES
  • Understanding of Faraday's Law of Electromagnetic Induction
  • Familiarity with Maxwell's Equations
  • Basic knowledge of electric and magnetic fields
  • Concept of free electrons in conductors
NEXT STEPS
  • Study the implications of Faraday's Law in practical applications
  • Explore Maxwell's Equations in detail
  • Investigate the behavior of electrons in electric and magnetic fields
  • Learn about electromagnetic induction in various materials
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Physics students, electrical engineers, and anyone interested in understanding the principles of electromagnetism and their applications in technology.

George_Tailor
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What cause potential difference in the conductor? I mean why the changing magnetic flux induce EMF? I understand the basics but I can't understand it. What I know: there is free electrons on the surface of a copper conductor. Electron have electric field vector and magnetic field vector and these are perpendicular. Electric vector point to the protons/core usually but these are delocalized electrons. In a changing magnetic flux these electrons always turn to the opposite side of flux with their magnetic vector but don't move. That's all, just turn. Why build it EMF? Where is the potential difference?
 
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Hello George! Welcome to PF! :smile:
George_Tailor said:
…there is free electrons on the surface of a copper conductor. Electron have electric field vector and magnetic field vector and …

No, you are treating "a changing magnetic flux" as if that is all there is.

You cannot have a changing magnetic field without an electric field …

Faraday's Law (one of Maxwell's equations) says ∂B/∂t = -curlE …

it's that E which cause the electric potential difference! :wink:​
 
tiny-tim said:
Hello George! Welcome to PF! :smile:


No, you are treating "a changing magnetic flux" as if that is all there is.

You cannot have a changing magnetic field without an electric field …

Faraday's Law (one of Maxwell's equations) says ∂B/∂t = -curlE …

it's that E which cause the electric potential difference! :wink:​


OK, I know the equation and all what you say. But what is the quantum physics explanation of this EMF? You mean if the magnetic field sort electrons in the same direction the electric field vectors of these also will point in one direction and this cause EMF? But why these electrons start to move in a short circuit?
 
George_Tailor said:
You mean if the magnetic field sort electrons in the same direction the electric field vectors of these also will point in one direction and this cause EMF?

Sorry, George, but I don't know what you mean. :confused:

A changing magnetic flux includes an electric field.

That electric field (obviously) affects the electrons, and it induces a current in a conductor.
 

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