## Topic outline

### Introduction and math prelims

We'll review what you covered in Physics 8 and some of the vector calculus tools we'll be using throughout the semester.

Before you start the reading (of course, if you started to review the material, that is no problem), please take no more than 30 minutes and print out and complete the E&M diagnostic provided on the course web site and hand it in no later than Weds 9/4 at noon. This diagnostic will help me see what you remember from your previous study of E&M, and will help me improve the first assignment and seminar. If you can turn it in earlier than the deadline, that is helpful! Further instructions are provided with the diagnostic.

This is a short section from Feynman's lectures on physics where he muses on the physical reality of fields... we'll be working with fields for the rest of the semester, and will have plenty of opportunity to continue to discuss issues related to their "reality".

This is a list of the main properties of the Dirac delta function (which is introduced in Griffiths' chapter 1). If you want some more information on exaclty what the Dirac delta function is, there is a great reference listed in this document.

Somtimes the best place to look for something is on Wikipeadia-- who am I kidding! Its always best to look on Wiki first. Here is a list of vector calculus identies that you will find useful throughout the semester (and beyond!).

- This topic
### Topic 2

A letter written by Franklin descirbing his kite experiment.

As you read last week, fields are mathematical objects with nearly no direct connection to our day-to-day existence (i.e., they are in no way mechanical in nature). Feynman dicusses the physics of a the height of a stretched rubber membrane, which is an analogy to the electrostatic potential field.

Feynman’s simple system which explains why lightening rods work... as an added bonus a discussion of a fascinating ‘microscope’ using the same principle– which can show you the structure of individual atoms on a metal tip!!!

A description of the various tests of Coulomb’s law that has used some variation on the experiment designed by Maxwell, and discussed in problem 3.

This Mathematica notebook shows you the commands you will need in order to compute and plot the electrostatic potential of a uniformly charged disk.

A Mathematica notebook showing how to use the ContourPlot command.

### Topic 3

A different textbook talking about electrostatic energy. Reading multiple textbooks serves to solidify concepts-- different authors will have different levels of rigor and different emphases. Some will appeal more strongly to you than others, but you really don't understand a concept until you've read about it in a few different contexts.

### Topic 4

This is James Clerk Maxwell's own introduction to his opus magnum "A Treatise on Electricity and Magnetism".

A Mathematica notebook which calculates the electrostatic potential of NaCl.

These notes describe the physics of a buckling card. There are more details in these notes than you will need for class (but if you want, the details are there). The beginning talks about how the non-linear nature of buckling causes a failure of the types of uniquness theorems that we have in electromagnetism. In addition, the non-linearity leads to a very interesting

*degeneracy*when it comes to the minimum of the energy of the system.

### Topic 6

How is it possible that people missed the direct connection between electricity and magnetism until Hans Chirstian Oersted did a demonstration as part of a lecture in 1820? Could there be experiments that we have not thought to do which may uncover an essential part of the physical world today?

### Topic 7

Did you know that hysteresis appears in systems other than the magnetization of a ferromagnet? Don't read this to understand the details of the physics, but to appreciate how hysteresis comes about in this system and think about how the hysteresis presented in this system can be used an analogy to understand what happens in a ferromagnet.

This is an excerpt from James Van Vleck's Nobel Lecture (1977). He gives a great review of magnetism and why quantum mechanics is essential to truly understand the magnetic properties of matter.

### Topic 9

Read these notes paying attention to the details– it will give you a better context in which to understand what a stress-tensor actually is.