Possible title: Surface Error in Faraday's Law Lecture?

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Discussion Overview

The discussion revolves around a potential error in a lecture on Faraday's Law, specifically regarding the treatment of surface integrals and magnetic flux through closed surfaces. Participants are examining the implications of a professor's statement about a closed surface in the context of Gauss's law for magnetism.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant questions whether the professor made an error by stating that the surface integral is closed, noting that according to Gauss's law for magnetism, the magnetic flux through a closed surface should be zero.
  • Another participant suggests that the professor is referring to the rate of change of flux through an area defined by a closed path, implying that the area has a single surface rather than being a closed surface.
  • A third participant expresses confusion about the response, pointing out that the professor drew a circle on the integral symbol, which they interpret as indicating a closed surface, thus leading to the conclusion that the magnetic flux should be zero.
  • One participant confirms that the closed loop integral of the electric field is related to the change in magnetic flux through an open surface attached to the loop, suggesting a distinction between closed and open surfaces in this context.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus, as there are competing interpretations of the professor's statement regarding closed surfaces and magnetic flux. The discussion remains unresolved with differing viewpoints on the implications of the lecture content.

Contextual Notes

Participants reference Gauss's law for magnetism and the relationship between closed and open surfaces in the context of Faraday's Law, indicating potential limitations in understanding or assumptions about the definitions involved.

teroenza
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Hello,

At approximately 4 min 48 sec. the professor indicates that the surface for the surface integral is closed. This contradicts my albeit limited knowledge in which the magnetic flux through a closed surface is zero (Gauss's law for magnetism). Did he make an error of is my understanding incomplete?

Thank you

http://www.youtube.com/user/YaleCourses#p/c/D07B2225BB40E582/10/E
 
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teroenza said:
Hello,

At approximately 4 min 48 sec. the professor indicates that the surface for the surface integral is closed. This contradicts my albeit limited knowledge in which the magnetic flux through a closed surface is zero (Gauss's law for magnetism). Did he make an error of is my understanding incomplete?

Thank you

http://www.youtube.com/user/YaleCourses#p/c/D07B2225BB40E582/10/E

I assume that your link is to #11 video.

He is saying that the rate of change of the flux through the area defined by the closed path is equal to the line integral of the electric field around that path. So the area he is speaking about has a single surface - the area enclosed by the path.

AM
 
I apologize, yes I meant video number 11 of the Yale phys 201 series. This link did not copy-and-paste correctly.
I do not quite understand your response. He drew a circle on the double integral symbol of the flux side of the equation, which would make it a closed surface, and thus make magnetic flux emanating from it equal to zero by Gauss's law, correct?
 
Last edited:
You're right:
The closed loop integral of E dot dl is minus the change in magnetic flux through the open surface attached to the loop.
 

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