Exam information

As always - you can bring the "purple equation sheet", your plasma equation book, and at this point three sides of handwritten notes (written by you!)

The final will be cumulative - (look below to remind yourself of the material that was expected on earlier midterms.) There will also be new stuff since the last midterm, primarily magnetism. I would expect it to be roughly "half and half" . As always, anything from homeworks, reading, and lecture all term are fair game, but I try to focus on big topics for exam questions. Chapter 7 will not be on the final.

If you never noticed, the syllabus has detailed (course-level but also chapter by chapter) learning goals.

Chapter 5 : Magnetic fields

Ampere’s Law, vector potential, and Biot-Savart are the center of this chapter. Know how to find the vector potential, how to use it to find the B-field. Know about volume, surface, and line currents and current densities. There’s a triangle diagram somewhere…

Chapter 6: Magnetic fields in Matter:

Know about magnetic dipoles and magnetic moments, especially how to add them up to yield the magnetic moment per unit volume. Know about the B, M, and H fields, bound currents from M, and Ampere's Law for the H-field. Know about linear magnetic materials and magnetic permiability.

Older information, for reference:

Here is the histogram from Exam 2:

Second midterm was Tuesday evening. Same basic structure as before.(see notes below)

• TWO sides of an 8.5x11 crib sheet will be allowed at the exam (handwritten, by you), You can also bring the purple sheet, and the "plasma Formulary" book.
• The exam is cumulative (obviously, material from Chapters 1 and 2 are not "going away" this term!) but we will focus on new material, Chapters 3 and 4.

The exam is going to center on Chapter 3 material (on electrostatic potentials in vacuum) and Chapter 4 material on static electric fields in matter. Since we have only had one homework on Chapter 4 material, I will "cut off" that material at (but including) chapter 4.4.1. So I *do* expect you to know the basics of the "D" field and linear dielectrics (the dielectric constant, and how it relates D, E, and P in a simple way).

Below, I have listed some of the high points that I think of as the core material. However, all of Chapter 3 - 4.4.1 and anything from homeworks and class are fair game!

Chapter 3: Poisson and Laplace equations:

Solving Laplace (in various coordinates) is the heart of the material. Know how to use the potential to find electric fields, and vice versa. This chapter included the method of images (do you understand the ideas behind this method?) the method of separation of variables (do you understand the method, so e.g. could you "separate variables" in a different coordinate system, or for a different differential equation?) and the approximation method known as the multipole expansion. (Do you know what the dipole moment is and how to find it? And what the potential looks like far away due to it?)

Chapter 4: E-fields in matter.

Know about electric dipoles and how to add them up via the polarization. In particular, you should be comfortable with the ideas of surface and volume bound charges, finding the D-field from known (simple, symmetric) free charge distributions, and how to relate the E-field to D and P for linear media. (i.e. know about relative dielectric constants) I will not give you a "nasty" boundary value problem with dielectrics like the examples in 4.4.2 (we'll save that for the next homework!) nor will I be asking about questions of energy or forces in dielectrics (4.4.3)

First midterm is Tuesday evening. (See below) Note the location, it is NOT our regular classroom!

• Here is the cover sheet for the exam (with instructions)
• ONE side of an 8.5x11 crib sheet will be allowed at the exam (handwritten, by you), You can also bring the purple sheet, and the "plasma Formulary" book.
• Click here for exam grading questions.
• If you were to get stuck on, oh, say, DOING an integral during the exam, ask me. I might tell it to you (perhaps docking a couple of points?) - but better that you can move on than that you get stuck on such a purely mathematical point...
• The exam is going to cover Chapter 2 material on Electrostatics and whatever Chapter 1 material you need to evaluate associated mathematical expressions. Below, I have listed some of the high points that I think of as the core material. However, all of Chapter 2 and Chapter 1 and anything from Homework Assignments 1-5, I consider fair game. I am going to list the gradient, divergence, and curl in the three major coordinate systems on the exam.

  If you understand and can use Griffiths triangular diagram, Figure 2.35 on page 87, and can calculate energies of assembly, then you are likely to do well on the exam.

  Chapter 1: Here are the major topics you should now know about:

  Vector calculus ideas like div, grad, and curl.

  Stokes and Gauss theorems

  Dirac delta functions. (in 1-D and also 3-D!)

  Chapter 2: Electrostatics.

  All sections. You should know about all the topics we covered in the homeworks. All the legs of Figure 2.35 should be familiar. In addition to being able to crank the equations, you should also know about some of the limiting cases, say for the expected electric field or voltage very far away from an object. Also, be prepared to know how to check your work, say by taking the divergence of an E-field to check that you get back the original charge distribution.

  Energy and capacitance problems are easy to forget as they don’t appear on Figure 2.35, but you need those tools too. Remind yourself about how to figure out configuration energies and capacitance.