Lecture 5: E = -grad V, More on Equipotential Surfaces, Conductors, Electrostatic Shielding (Faraday Cage)

author: Walter H. G. Lewin, Center for Future Civic Media, Massachusetts Institute of Technology, MIT
recorded by: Massachusetts Institute of Technology, MIT
published: Oct. 10, 2008,   recorded: February 2002,   views: 3864
released under terms of: Creative Commons Attribution Non-Commercial Share Alike (CC-BY-NC-SA)

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"So today no new concepts, no new ideas, you can release a little bit and I want to discuss with you the connection between electric potential and electric fields.

Imagine you have an electric field here in space and that I take a charge Q in my pocket, I start at position A and I walk around and I return at that point A.

Since these forces are conservative forces, if the electric field is a static electric field, there are no moving charges, but that becomes more difficult, then the forces are conservative forces and so the work that I do when I march around and coming back at point A must be zero. It's clear when you uh look at the equation number three that the potential difference between point A and point A is obviously zero. I g- start at point A and I end at point A and that is the integral in going from A back to point A of E dot DL and that then has to be zero.

And we normally indicate such an integral with a circle which means you end up where you started. This is a line now this is not a closed surface as we had in equation one..."

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Reviews and comments:

Comment1 mesut türk, March 10, 2009 at 12:57 a.m.:

can you make this videos downloadable on rapidshare or somewhere else. I want to make archieve your lectures :)

Comment2 lzamarro, July 31, 2013 at 7:15 p.m.:

My english is not very good. I need all the subtitles. Please.
Thank you.

Comment3 Andrew, August 30, 2018 at 6:30 a.m.:

A Faraday cage or Faraday shield is an enclosure used to block electromagnetic fields. A Faraday shield may be formed by a continuous covering of conductive material or in the case of a Faraday cage, by a mesh of such materials. https://mcdvoice.me/

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