Lecture 9: Currents, Resistivity, Ohm's Law
recorded by: Massachusetts Institute of Technology, MIT
published: Oct. 10, 2008, recorded: February 2002, views: 23115
released under terms of: Creative Commons Attribution Non-Commercial Share Alike (CC-BY-NC-SA)
Download mit802s02_lewin_lec09_01.m4v (Video - generic video source 102.8 MB)
Download mit802s02_lewin_lec09_01.rm (Video - generic video source 78.4 MB)
Download mit802s02_lewin_lec09_01.flv (Video 213.3 MB)
Download mit802s02_lewin_lec09_01_320x240_h264.mp4 (Video 143.6 MB)
Download mit802s02_lewin_lec09_01.wmv (Video 408.3 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.
"When positive charges move in unintelligible directions, then per definition, we say the current goes in this direction. When negative charges go in this direction, we also say the current goes in that direction, that's just our convention. If I apply a potential difference over a conductor, then I'm going to create an electric field in that conductor. And the electrons -- there are free electrons in a conductor -- they can move, but the ions cannot move, because they are frozen into the solid, into the crystal.
And so when a current flows in a conductor, it's always the electrons that are responsible for the current. The electrons fuel the electric fields, and then the electrons try to make the electric field zero, but they can't succeed, because we keep the potential difference over the conductor..."
Link this pageWould you like to put a link to this lecture on your homepage?
Go ahead! Copy the HTML snippet !