About the midterm exam

It will be an oral exam. Schedule a half-hour appointment with Paul once you have solved the problem(s) below and studied to your satisfaction.

Bring

  • Your solution to Problem 2.45 (Energy of charged sphere, $\rho(r)=kr$ in the sphere and therefore it's not a conductor.) The first step is find the electric field everywhere...
  • Your solution to Problem 2.48 (Vacuum diode).
  • 8.5 $\times$ 11" sheet of hand-written notes.
  • writing instruments.

    You will be given a photocopy, or access to the material inside the front and back covers of Griffiths. (E.g. curls and gradients in different coordinate systems, physical constants, etc.)

    Chapter 1

    • Differentiation, $\myv \grad$, $\myv \grad\cdot$, $\myv \grad\times$.
    • Line, surface, volume integrals.
    • Fundamental theorem for gradients (Relation of $\myv E$ to $V$).
    • Fundamental theorem for divergence (basis of Gauss' law).
    • Cartesian and non-Cartesian coordinate systems.
    • Dirac delta functions.

    Chapter 2 - Electrostatics

    • Coulomb's law, the electric field, principle of superposition.
    • Integrating over a continuous charge distribution to get $\myv E$.
    • Electric field lines (qualitative), conventions for drawing
    • Divergence of the electric field $\myv \grad\cdot E=\frac{1}{\epsilon_0}\rho$. Gauss' law: meaning and application. Fields in high-symmetry situations (planes, spheres, cylinders).
    • $\myv \grad \times \myv E=0$ (curlless field) implies that there's a potential $V$ such that $\myv E=-\myv \grad V$. Integrating $\myv E$ to get potential differences.
    • Griffith's figure 2.35 is a summary of relations between $\myv E$, $V$, and $\rho$.
    • Work / energy of charge distributions
    • Conductors
    • Capacitance