Lecture 8: Polarization, Dielectrics, The Van de Graaff, More on Capacitors

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: 2607
released under terms of: Creative Commons Attribution Non-Commercial Share Alike (CC-BY-NC-SA)
Categories

See Also:

Download slides icon Download slides: dielectrics_and_polarization.pdf (162.0 KB)

Download Video - generic video source Download mit802s02_lewin_lec08_01.m4v (Video - generic video source 106.0 MB)

Download Video - generic video source Download mit802s02_lewin_lec08_01.rm (Video - generic video source 81.3 MB)

Download Video Download mit802s02_lewin_lec08_01.flv (Video 190.6 MB)

Download Video Download mit802s02_lewin_lec08_01.wmv (Video 448.7 MB)


Help icon Streaming Video Help

Related content

Report a problem or upload files

If 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.
Lecture popularity: You need to login to cast your vote.
  Bibliography

Description

"Electric fields can induce dipoles in insulators.

Electrons and insulators are bound to the atoms and to the molecules, unlike conductors, where they can freely move, and when I apply an external field -- for instance, a field in this direction, then even though the molecules or the atoms may be completely spherical, they will become a little bit elongated in the sense that the electrons will spend a little bit more time there than they used to, and so this part become negatively charged and this part becomes positively charged, and that creates a dipole.

I discussed that with you, already, during the first lecture, because there's something quite remarkable about this, that if you have an insulator -- notice the pluses and the minuses indicate neutral atoms -- and if now, I apply an electric field, which comes down from the top, then, you see a slight shift of the electrons, they spend a little bit more time up than down, and what you see now is, you see a layer of negative charge being created at the top, and a layer of positive charge being created at the bottom.

That's the result of induction, we call that also, sometimes, polarization. You are polarizing, in a way, the electric charge..."

Link this page

Would you like to put a link to this lecture on your homepage?
Go ahead! Copy the HTML snippet !

Reviews and comments:

Comment1 Swati Roy, May 18, 2011 at 6:57 a.m.:

Sir,
Hats off to you, you are simply awesome
Regards
Swati


Comment2 MIMO, December 7, 2011 at 9:10 a.m.:

DSir,
i dunno if u'll see this comment or not .. or even u r dead or still alive ..
but i dream to be like you oneday .. or even better


Comment3 Ebrahin saffari, May 27, 2014 at 5:14 p.m.:

Dear prof. Walter Lewin.
Would you please let me know how can i have the
complete text of your speech as one paragraph is brought on the top. I will appreciate very much if you help me
i hope you will help me. Thanks alot
your very truly
e. saffari


Comment4 ibrahim çetin sağında, March 14, 2015 at 4:02 p.m.:

awesome


Comment5 Walter Lewin, October 6, 2015 at 10:18 a.m.:

... will produce an electric field

Write your own review or comment:

make sure you have javascript enabled or clear this field: