1
Energy stored in Electric Field
Work to move dq up the field:
But q and V are related via C:
+dq
Move dq from
1 to 2, one by
one
dq
+q
+dq
Start from both conductors
with q=0, and integrate
q
Keep moving
against the field.
General Physics II, 171.102
1
BiotSavart Law
Sources of magnetic field:
permanent magnets need Quantum Physics to understand
currents
Experiments show how the B
field is oriented near conductors
General Physics II, 171.102
Lecture 19
2
BiotSavart Law
Experiment:
B field lines are
Atomic spectra
1
Immensely useful.
But why are there
lines? Why discrete?
General Physics II, 171.102
Lecture 38
2
Wave function
Matter particles (e.g. electron) are described by their wave
function:
it's a complex number
is a probability density to obser
Second Midterm
Physics 106
April 18, 2012
Do this exam by yourself. No calculators or books are needed or permitted. However,
a formula sheet is (two pages of US letter size paper). Problems are on BOTH SIDES
of this page. Please explain your reasoning. D
Second Midterm
Physics 106
April 19, 2013
Do this exam by yourself. No calculators or books are needed or permitted. However, a
formula sheet is (one page of paper of any size) is allowed.
Problems are on BOTH SIDES of this page. Please explain your reaso
First Midterm
Physics 106
March 11, 2013
Do this exam by yourself. No calculators or books are needed or permitted. However, a
formula sheet is (one page of paper of any size) is allowed.
Problems are on BOTH SIDES of this page. Please explain your reason
1
Limitation's of Ohm's Law
DrudeLorenz's model describes
conduction of a variety of materials
and under a variety of conditions (esp. room temperature)
dependence on temperature, etc. (e.g. `Hall effect')
Nevertheless, it's just a model
IV curves for f
Circuit rules
Ohm's Law:
For capacitors:
1
on any resistor
on any capacitor
Conservation of charge current into any junction is
conserved!
Junction rule, Kirchoff's 1st rule, etc.
sum of voltages around any loop is zero!
Loop rule, Kirchoff's 2nd rule, et
Ampere's Law
If no currents enclosed:
Contour can have an arbitrary shape
Could enclose multiple currents
Very powerful statement about property of B field
1
With symmetry, a good way to determine B
(Similar symmetries in play as for Gauss's Law)
General
1
Magnetism
General Physics II, 171.102
(Lodestone
in the
Smithsonian)
Lecture 17
2
Early magnets
Lodestone: Greeks
or Chinese
First compass:
Han dinasty: divination
~ 1000 AD: navigation
lodestone: lead stone,
needle floating in water
Gilbert (1600): fir
1
Capacitance (3)
Double q V doubles. (Halve q V is halved, etc.)
q is proportional to V
CAPACITANCE
Capacitance:
property of the system (not the charge)
.i.e. of shapes and sizes of conductors
units: Farad, 1F = 1C/1V
General Physics II, 171.102
Lecture
1
Induced dipole moment
Clicker: the coke can will
A) be repulsed by charge rod
B) be attracted by charged rod
C) not move
General Physics II, 171.102
Lecture 8
2
Induced dipole moment
Clicker: the coke can will
A) be repulsed by charge rod
B) be attracte
Electric Potential: basics
Electric Potential:
Property of fixed charges not
1
Integral independent of path closed path:
!
a scalar field
Unit: Volt
Potential of the single charge:
General Physics II, 171.102
[V] = joule / coulomb = 1 V
Lecture 10
Potenti
1
Electric Potential: basics
Electric Potential:
Property of fixed charges not
Integral independent of path closed path:
!
a scalar field
Unit: Volt
Potential of the single charge:
General Physics II, 171.102
[V] = joule / coulomb = 1 V
Lecture 9
2
Electr
Solving Maxwell's eqns. in empty space (4)
1
Notes:
1) solutions depend on both x and t!
2) E(x,t) and B(x,t) have same dependence on x and t!
3) (enforced by construction)
General Physics II, 171.102
Lecture 31
2
Maxwell's equations in matter
Maxwell's e
1
Current
So far, we talked about electrostatics
When
applied to conductors charges move = current
General Physics II, 171.102
Net charge per unit time
through some crosssection A
= Flux of charge
Unit: Ampere
Lecture 13
2
Current density
Charge carriers
1
RC Circuits
switch
+
+ +

charging
+
+
discharging
General Physics II, 171.102
Circuit which contains both a
R and a C
Charges move from battery
onto plates of C
Potential energy is being
loaded into the capacitor
Flip the switch
Charges move from the
Atomic spectra
1
Immensely useful.
But why are there
lines? Why discrete?
General Physics II, 171.102
Lecture 36
The birth of Quantum Mechanics
Werner Heisenberg (1925, at age 24)
invents matrix mechanics
2
(with help of Born and Jordan)
first serious use
Physics 171.106
Midterm Exam 1
March 14th, 2006
Answer all four problems. Be sure that you pace yourself so that you have enough time
to work on each problem. Note that the problems do not have equal weight. Partial
credit will be given, so be sure to sho
Physics 171.106
Midterm Exam 1
March '7, 2005
Answer all four problems" Be sure that you pace yourself so that you have enough time
to work on each problem, Note that the problems do not have equal weight. Partial
credit will be given, so be sure to show
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Final Exam
Physics 106
May 14, 2013
Do this exam by yourself. No calculators or books are needed or permitted. However, a
formula sheet is (one page of paper of any size) is allowed.
Problems are on BOTH SIDES of this page. Please explain your reasoning.