3 Gauss's law and static charge densities
We continue with examples illustrating the use of Gauss's law in macroscopic field calculations:
Example 1: Point charges Q are distributed over x = 0 plane with an average surface charge density of s C/m2 . Deter

11 Lorentz-Drude models for conductivity and susceptibility and polarization current
In this lecture we will describe simple microscopic models for conductivity and electric susceptibility e of material media composed of free and bound charge carriers. Th

10 Capacitance and conductance
Parallel-plate capacitor: Consider a pair of conducting plates with surface areas A separated by some distance d in free space (see margin). The plates are initially charge neutral, but then some amount of electrons are tran

9 Static fields in dielectric media
Summarizing important results from last lecture: within a dielectric medium, displacement D= E=
oE
+ P,
and if the permittivity = r o is known, D and E can be calculated from free surface charge s or volume charge in t

8 Conductors, dielectrics, and polarization
We have so far been examining static field configurations of charge distributions assumed to be fixed in free space, in the absence of materials (solid, liquid, or gas) composed of neutral atoms and molecules.

7 Poisson's and Laplace's equations
Summarizing the properties of electrostatic fields we have learned so far, they satisfy the constraints D = and in addition E = - V as a consequence of D= from which it follows that
2
E = 0 where D =
o E;
E = 0. ( V )

6 Circulation and boundary conditions
Since curl-free static electric fields have path-independent line integrals, it follows that over closed paths C (when points p and o coincide)
C
z y dS C S o=p
lj Ej
E dl = 0,
where the C E dl is called the circulati

5 Curl-free fields and electrostatic potential
Mathematically, we can generate a curl-free vector field E(x, y, z) as E = -( V V V , , ), x y z
by taking the gradient of any scalar function V (r) = V (x, y, z). The gradient of V (x, y, z) is defined to b

4 Divergence and curl
Expressing the total charge QV contained in a volume V as a 3D volume integral of charge density (r) we can express Gauss's law examined during the last few lectures in the general form D dS = dV.
V
S
This equation asserts that the f

POSC 104.01
American People and Politics
Professor Chris Soper
Arcade Fire: Wake Up
http:/www.youtube.com/watch?v=9zdNdjF-htY
What is your passion?
Who Cares?
Wake up!
What is the Purpose of
Government?
To Preserve Order
- in the state of nature, the li