(You call that a capacitor? Now THIS is a capacitor!) A commercially available capacitor: 2.7 volts, 3000 Farads. Making "ultracapacitors" like this requires going beyond just a simple old-fashioned "thin film dielectric" like we're talking about in class this week ... Using the formula C = ε _r ε₀ A/d, even with d as small as 1 nm (how much closer could 2 plates ever get?) and a rather spectacular dielectric constant of, say, 100, you'd still need to squeeze an effective plate area of far more than a football field, all rolled up to fit into this little battery-sized container!)

Week 9 (Mar 11-Mar 15):

We're continuing with Chapter 4 this week, studying electric fields in matter - "dielectrics".

Special notes:

• NOTE: I will not cover 4.4.3, the last section of Ch 4, in any detail.
• Preflight #9 (dielectrics) is due Friday Mar 15 (before class, as usual)
  
  
• Next homework is HW 9 (Due Wed Mar 13)
• Next homework is HW 10 (Due Wed, Mar 20, with an automatic extension to Friday if you need it)
  There is an extensive hint for the last question (try it first!) , and a Tutorial which serves to guide you through the Extra credit, if you want it!
  
  
  
• Please visit our piazza site. I give extra credit for participation there. (The more who do that, the more useful it becomes to the rest of us.)
  We also have a D2L (learn.colorado.edu) site - I post solutions there
  
• Video lectures:here.
  
  

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  OLDER Webpages, for reference and old links: Week 1, Week 2, Week 3, Week 4, Week 5, Week 6, Week 7, Week 8,
  
  

I welcome your comments on the class and this website. Send them to steven.pollock at colorado.edu
(Thanks to Prof. Chuck Rogers for many of our home page image ideas!)