Lecture 7: Capacitance, Field Energy
recorded by: Massachusetts Institute of Technology, MIT
published: Oct. 10, 2008, recorded: February 2002, views: 29534
released under terms of: Creative Commons Attribution Non-Commercial Share Alike (CC-BY-NC-SA)
Download slides: capacitance_of_spheres.pdf (15.4 KB)
Download mit802s02_lewin_lec07_01.m4v (Video - generic video source 102.9 MB)
Download mit802s02_lewin_lec07_01.rm (Video - generic video source 78.7 MB)
Download mit802s02_lewin_lec07_01.flv (Video 208.8 MB)
Download mit802s02_lewin_lec07_01.wmv (Video 412.5 MB)
Report a problem or upload filesIf you have found a problem with this lecture or would like to send us extra material, articles, exercises, etc., please use our ticket system to describe your request and upload the data.
Enter your e-mail into the 'Cc' field, and we will keep you updated with your request's status.
"...assemble charges, I have to do work, we discussed that earlier. And we call that electrostatic potential energy. Today, I will look at this energy concept in a different way, and I will evaluate the energy in terms of the electric field. Suppose I have two parallel plates, and I charge this one with positive charge, which is the surface charge density times the area of the plate, and this one, negative charge, which is the surface charge density negative times the area of the plate. And let's assume that the separation between these two is H, and so we have an electric field, which is approximately constant, and the electric field here is sigma divided by epsilon zero.
And now, I'm going to take the upper plate, and I'm going to move it up. And so as I do that, I have to apply a force, because these two plates attract each other, so I have to do work. And as I move this up, and I will move it up over distance X, I am creating here, electric field that wasn't there before...."
Link this pageWould you like to put a link to this lecture on your homepage?
Go ahead! Copy the HTML snippet !