Physics 131 Electromagnetic Theory I

Announcements

⭐ Submission form for NB1 (due 14 Oct 2026) click here.

Week 2: 26-28 August
Reference: GR 1
☐ Provide geometrical interpretations or physical examples for the gradient, divergence, and curl. Make a sketch or add a plot that you have made to illustrate these (point) derivatives.
☐ Provide geometrical interpretations or physical examples for the fundamental theorem for gradients, divergences, and curls.
☐ Write down Laplacian for an orthogonal coordinate system in terms of its scale factors. Verify this formula for cylindrical and spherical coordinates.
☐ Prove that the divergence of a radial inverse-square power vector field is consistent with a Dirac-delta point source or sink.

Week 3: Sep 2-4: Electrostatics: The electric field
References GR 2
☐ Write down the expression for the electric field E(r) due to a continuous charge distribution ρ(r). Use
sketches that show how the field E at the field point r is integrated over differential elements about source points r'.
☐ Write down and give a brief physical description for the Maxwell’s equations that involve the divergence and curl of E.
! For charge distributions ρ(r) that are symmetric, the construction of Gaussian surfaces with the same
symmetry allows one to readily obtain electric fields by the divergence theorem.
! When charge distributions are constant in time or when current distributions are constant in time, the curl of the associated electric field is zero.
☐ Consider a dipole with charge q with separation distance a and dipole moment p = qa. Evaluate the electric potential and electric field due to this configuration. Then take the point dipole limit a → 0 with p finite. Find the far-field electric potential and electric field.

Week 4: Sep 9-11 Electrostatics: Boundary conditions, work and energy, conductors
References GR 2
☐ Give the continuity conditions on the electric field and potential across interfaces.
☐ Show that the energy needed to set up a particular charge distribution given initial sources far away from each other can be obtained from the scalar potential.
☐ Provide the features of conductors that are relevant to determining the distribution of charges in them at electrostatic equilibrium.
☐ Briefly discuss how induced charges are set up on the surfaces of conductors in the presence of external electric fields.
☐ Prepare for a short quiz in the next on-site meeting. 

Week 5/6: Sep 16-25 Electrostatics: Potentials
References GR 3
☐ Discuss the importance and advantages of formulating EM in terms of potentials (specifically for electrostatics).
☐ Give the relationship (Maxwell's equations) between the scalar potential and the electrostatic field.
☐ Enumerate the steps leading to a solution to Poisson's equation using Sturm-Liouville theorem techniques (separation of variables, eigenfunction expansion).
☐ Enumerate the steps leading to a solution to Poisson's equation using a Green's function solution.
☐ Use both techniques to solve a boundary value problem with fixed boundary conditions (you can choose your own example, in two or three dimensions).

Week 7: Sep 30 - Oct 1 Electrostatics: Multipole expansion
! One problem in the midterm will involve using multipole expansion techniques.

Midterms: 07 October 2026, in class. If suspended by UPD or LGU, next on-site class. Coverage is Griffiths Ch 1-3. Open paper notes.

Week 8: 14-16 Oct: Electric displacement
References GR 4
☐ Make a clear distinction between the conventional “free” and “bound” charges described in the textbook.
☐ Show how Gauss’s law is modified in the presence of a polarization field P. Make sure to label with
complete physical descriptions each term in the definition of the electric displacement field D.
☐ Describe a linear dielectric in terms of the relationship between the polarization and electric fields.
☐ Give the boundary conditions (normal and tangential) on the electric field E and displacement field D at a boundary between two dielectric media.

Week 9 21-23 Oct: Energy in dielectrics
References GR 4
☐ Show that the work needed to charge a dielectric capacitor, and hence the energy stored in it, increases with the relative permittivity of the dielectric.

⭐ Notebook: Due 14 October 2026, through Google Drive submission link (click here). Coverage Weeks 1-6.


Class requirements:
You must submit two (2) notebook files, one (1) problem set, and take one sit-in midterm exam to complete the course. Notebooks and problem sets may be handwritten or typeset, but the submission must be a PDF file to be submitted through an online form. The submission link will be provided on the course webpage. You must submit your work by the deadline, otherwise the work will be considered a non-submission. The submission bin will close 48 hours after the deadline as a grace period, and late submissions within this period must be accompanied by a University-recognized excuse.
On-site attendance will be checked to comply with University attendance requirements.
Progress will be monitored by performing two types of checkpoint activities:
1. ☐  Notebook entries
You must submit two notebook files (one around midterm, and another before the finals week). Each file must contain weekly notebook entries with a new section or page made for each week. Each entry should demonstrate that each box-bulleted ☐ outcome item in the syllabus has been achieved. For example, you can write a short summary or outline of the topic, or give a list of steps in the derivation of a core result, or provide a worked out representative example. I suggest that you monitor your progress by ticking each box ☐ in this course guide as you complete these notebook entries. By the end of the semester you will have a notebook that you can use as a handy reference as you progress in the BS Physics/BS Applied Physics program.
2. Problems
You must submit one problem set to be given later in the semester. You are encouraged to discuss these problems with your classmates and help each other, but you must work independently and write up your own reports and solutions. You can also ask me for help. It is recommended to do the problems in parallel with the learning units, but you can work on them in any order and at your own pace.

Assessment
There will be one problem set, one midterm exam, and two notebook submissions required in this class. Each problem set, exam, and notebook submission will contribute equally to the final grade.The problem set, midterm exam, and notebook files must be submitted: a grade of INC will be given if one of the four requirements are not submitted in class (for the midterm) or via the submission bin; a grade of 5.0 will be given if two or more requirements are not submitted. At most one non-submission or 0-graded requirement may be replaced by taking a comprehensive written final examination during the Finals week.
On-site attendance will be checked to comply with University attendance requirements.
Academic integrity: You are encouraged to collaborate with your classmates and use reference texts to help you with your problem sets. However, you must submit solutions that you have written independently.
College of Science statement: Any form of cheating in examinations or any act of dishonesty in relation
to studies, such as plagiarism, shall be subject to disciplinary action.