electrodynamics

"I have also a paper afloat, with an electromagnetic theory of light, which, till I am convinced of the contrary, I hold to be great guns."

Welcome to Physics 351! In this class we will study charges, currents, electric and magnetic fields, and their interactions. Much of the physics is expressed in a single, remarkable set of equations

\begin{gather} \vec{\nabla} \cdot \vec{E} = \frac{1}{\epsilon_{0}} \rho \vphantom{\frac{\partial\vec{B}}{\partial t}} \\ \vec{\nabla} \times \vec{E} + \frac{\partial\,\vec{B}}{\partial \,t} = 0 \\ \vec{\nabla} \cdot \vec{B} = 0 \vphantom{\frac{\partial\vec{B}}{\partial t}}\\ \vec{\nabla} \times \vec{B} - \mu_{0}\,\epsilon_{0}\,\frac{\partial\,\vec{E}}{\partial\,t} = \mu_{0}\,\vec{J} \end{gather}

This formulation of electromagnetism is due primarily to the Scottish physicist James Clerk Maxwell. His equations, in one form or another, describe phenomenon ranging from the propagation of light to the deflection of a compass needle by a magnetic field.

The impact of Maxwell's equations extends well beyond electromagnetism: the Theory of Special Relativity is hidden inside them, and they are the prototype for a unified description of the basic forces of Nature.

Syllabus

Basic information about our schedule, homework assignments, grades, and more can be found below. Click here to download a pdf version of the full syllabus. The syllabus has more detailed information, and you should be familiar with the policies and rules it describes.

Fall 2026 Schedule

At a minimum we will cover the first seven chapters of the textbook and parts of chapters 8 and 9. Hopefully we will also cover portions of chapters 10 and 11. The timeline below is an estimate of how we would do that.

Week	Dates	Chapter
1	August 24, 26, 28	1
2	August 31; September 2, 4	1, 2
3	September 7, 9, 11	Labor Day; 2
4	September 14, 16, 18	2
5	September 21, 23, 25	3
6	September 28, 30; October 2	3, Exam 1
7	October 5, 7, 9	Fall Break; 3, 4
8	October 12, 14, 16	4
9	October 19, 21, 23	5
10	October 26, 28, 30	5
11	November 2, 4, 6	6
12	November 9, 11, 13	7, Exam 2
13	November 16, 18, 20	7, 8
14	November 23, 25, 27	9; Thanksgiving
15	November 30; December 2, 4	10, 11
16	December 11	Final Exam (9-11 am)

If you are engaged and active in class we can go faster, which will let us cover additional (interesting!) material from chapters 10 and 11.

Assignments

Homework is assigned each week (except for exam weeks) and collected the following week. With a few exceptions it will usually be due on Monday at the beginning of class. That way you can ask questions during our Friday discussion section.

Only some of the problems from each assignment will be graded. I won't tell you which ones, so you need to complete them all. We will talk more about how this works in class. Current and past assignments are listed below. You can see solutions for some (not all) problems, but they are not available for download. Please stop by my office if you'd like to see solutions for a particular assignment.

Working with classmates on these assignments is encouraged! But you should only hand in work you've completed on your own. If your solution looks just like someone else's work then you need to go back and redo it from scratch. If you can't explain each step of your solution then you haven't completed the problem on your own. Remember: the only way to be ready for the exams is to do the homework yourself.

Grades

Grades in this course are mostly based on homework assignments and exams. The weekly homework grades contribute 30% of your final grade in the class, and two exams (October 2 and November 13) count 17.5% each. A cumulative final exam (December 11, from 9 - 11 am) is worth 30%. The remaining 5% depends on attendance and participation. Asking questions, taking advantage of office hours, and attending both lectures and discussion sections will earn you the full 5%. Check the syllabus for more details.

References

The main text for the class is Introduction to Electrodynamics by David Griffiths. The book is currently in its 5th edition, but a copy of the 3rd or 4th edition is perfectly good for this class. The tone of the book is casual and most students find it very accessible. When I was an undergraduate we used the textbooks by Wangsness and Purcell. They might be helpful if something in Griffiths isn't clear. A more advanced treatment is Classical Electrodynamics by J. D. Jackson. It is used in practically every graduate E&M course.

1. Introduction to Electrodynamics
   David J. Griffiths
   
2. Electromagnetic Fields
   Roald K. Wangsness
   
3. Electricity and Magnetism
   Edward M. Purcell
   
4. Classical Electrodynamics
   J.D. Jackson
   

Griffiths' book has a very complete (for our purposes) discussion of vector calculus. If you'd like to see this material in more detail, I recommend the math methods book by Boas, or the book by Riley, Hobson, and Bence. There's also the graduate textbook by Arfken and Weber. It's more advanced, but your Math Methods class gave you all the preparation you need.

1. Mathematical Methods in the Physical Sciences
   Mary L. Boas
   
2. Mathematical Methods for Physics and Engineering
   K.F. Riley, M.P. Hobson, and S.J. Bence
   
3. Mathematical Methods for Physicists
   George Arfken and Hans Weber

The Feynman Lectures on Physics, which include a few nice discussions about some of the things we'll talk about in class, are available online. The Physics Club should also have a copy downstairs.

Lecture Notes

Notes

From time to time I will supplement material from the textbook with my own notes, which will be posted below.

E&M Stress Relief

Sometimes the E&M wears you out, and the only thing that can get you back on track is a picture of a little kid doing physics. Here you go.