TO DO list for PHYS 406, Spring, 2025:
Field, Force, Energy and Momentum in Classical Electrodynamics

Class Discussion Page on Piazza
Syllabus

Tentative Schedule

Problem Sets

Date

Topics
Beyond the Realm
of Common Discourse

Reading Assignments
(To be read in
preparation for meetings)

Goals / Links
for the Week

Vector Calc HW #1 Due Fri., Jan. 10: Piazza Note @7

HW Set#1a Due Monday, Jan. 13:
From Piazza Note@6 (which is not the Purcell text):
1.2 (read page 8), 1.3, 1.6, 1.7 (ask me for the answer), 1.12, 1.15, 1.18

HW Set#1b Due Friday, Jan. 17:
Purcell Ch 1:
Problems 1.7, 1.15; Exercises 1.36, 1.61, 1.62, 1.65, 1.81

Pre-Term

Div, Grad, Curl,
and All That;

and

Electrostatics Review

Piazza Note@6:
3D Vector Calculus

and

Purcell thru Sect. 1.4: The range of applicability

Jan. 8

Review of topics from Intro Physics

Purcell thru Sect. 1.8,
and
More on 3D Vector Calculus

Jan. 10

In-class, at-the-board, discussion of HW problems

More on Vector Fields,
and
Purcell thru Sect. 1.14

Celebrate National Static Electricity Day!

Of course, we'll take things further:




Science moves forward as a large, shared conversation,
so register NOW, for free access
to Physics World



Weekly Goal: appreciate Mary Boas



HW Set# 2a Due Monday, Jan. 20:
From Piazza Note@6 (which is not the Purcell text):
1.25, 1.27, 1.28, 1.31 (re-read Example 1.8), 1.32, 1.33, 1.34, 1.39

HW Set# 2b Due Friday, Jan. 24:
Purcell Ch 2:
Problems 2.5, 2.24, 2.25, 2.28, 2.30; Exercises 2.31, 2.32, 2.34, 2.73, 2.75, 2.78

Jan. 13


HW#1a is due today, so please check Piazza.

Post questions!
Try to respond
to questions posted by other students!

Purcell thru Ch 1 Summary

Jan. 15


Key Examples

Purcell thru Sect. 2.5

Jan. 17


Differential forms

Laplace is your friend!

Line integral of E

The potential function
(V or φ)

Finding E from V

Purcell thru Sect. 2.7.2


(Related topics: doping of semiconductors, ion implantation,
Bragg peak, proton therapy, ...)

PositiveFeedback

One of our IWU Physics grads works at the Department of Energy's Advanced Photon Source,
and at the Stanford Linear Accelerator (SLAC),
where charged particles are accelerated close to the speed of light,
to help develop materials for next-generation computers.
Modern engineering is often well beyond the range of common experience!


HW Set# 3a Due Monday, Jan. 27:
From Piazza Note@6 (which is not the Purcell text):
1.49, 1.57, 2.6, 2.7 (do not use Gauss’s Law), 2.21, 2.28, 2.34, 2.50

HW Set# 3b Due Friday, Jan. 31:
Purcell Ch 3:
Problems 3.11, 3.17; Exercises 3.38, 3.52

Jan. 20



Rules of the Game

Conservative fields



Purcell thru Sect. 2.13

Jan. 22



Games we play
when there's no curl


Purcell thru Ch 2 Summary

Jan. 24


Boundary Conditions:

Conductors in Electrostatics


Purcell thru Sect. 3.3

PositiveFeedback
When does a Philosophy Student become a Philosopher?
...Begin by grappling with some questions:

ONLY check the answers (below) after you've contributed your own thoughts!

Weekly Goal: appreciate the centrality of the conservation principles



HW Set# 3a
Due Monday, Jan. 27:
From Piazza Note@6 (which is not the Purcell text):
1.49, 1.57, 2.6, 2.7 (do not use Gauss’s Law), 2.21, 2.28, 2.34, 2.50

HW Set# 3b
Due Friday, Jan. 31:
Purcell Ch 3:
Problems 3.11, 3.17; Exercises 3.38, 3.52

HW Set# 4
(Don't delay getting started)
Due Friday, Feb. 14:
Purcell Ch 4: Problems 4.1, 4.2, 4.17; Exercises 4.19, 4.20, 4.29, 4.30; Ch 5 Problem 5.1

Jan. 27


The Method of Images suggests that, in a particular sense,
Metals
behave like
MIRRORS!


Keep this in mind while revisiting Capacitance

Purcell thru Sect. 3.5

Jan. 29


Bookkeeping

Multiple conductors

Relaxation Method

Purcell thru Ch 3 Summary

Jan. 31


Conservation Laws
in Materials:
Feynman Ch 27

Review!


PositiveFeedback
For the past 16 years, one of our IWU Physics grads has worked at National Electrostatics Corp. (After noting the applications for their first type of accelerators, keep scrolling to see the applications of other types)


...or, you might be interested by the use of high voltage for electrical special effects in movies



Weekly Goal: appreciate that all information is physical




HW Set# 4 Due Friday, Feb. 14:

(Don't delay getting started!)
Purcell Ch 4: Problems 4.1, 4.2, 4.17; Exercises 4.19, 4.20, 4.29, 4.30; Ch 5 Problem 5.1

Feb. 3

EXAMINATION I
coverage extended
through the end of
Purcell Ch 3

Review!

Feb. 5

Currents ain't electrostatic!

Eqn. 4.10 is a continuity equation.
Continuity equations are key!

p. 183 introduces Tensors (top, and footnote)
(More to come!)

Ponder Fig 4.6

Purcell thru Sect. 4.3

Feb. 7

Continuity,
Divergence,
and Flux

Purcell thru Sect. 4.5








Weekly Goal: Embrace who we are!




HW Set# 4 Due Friday, Feb. 14:

(Don't delay getting started!)
Purcell Ch 4: Problems 4.1, 4.2, 4.17; Exercises 4.19, 4.20, 4.29, 4.30; Ch 5 Problem 5.1



HW Set# 5a Due Wednesday, Feb. 19:

Purcell Ch 5: Exercises 5.10, 5.11, 5.13
(Start early on next set)

Feb. 10



Semiconductors
and more!

Purcell thru Sect. 4.9

Feb. 12


Circuits
that are
complicated
(in space
or
in time)

Purcell remainder Ch 4

Feb. 14


Origins of Magnetic Fields

(Be sure to
watch the
videos
at right)

Purcell thru Sect. 5.5

Magnetism is always a consequence of Einstein's Relativity:




Only after watching the SERIES of videos above can you appreciate why:


Weekly Goal: appreciate Linear Algebra



HW Set# 5a Due Wednesday, Feb. 19:

Purcell Ch 5: Exercises 5.10, 5.11, 5.13


(Start early on next set)


HW Set# 5b Due Monday, Mar. 3:

Purcell Ch 6: Problem 6.2; Exercises 6.29, 6.30, 6.31, 6.33, 6.42

Feb. 17


Did you
watch
last week's
videos
at right?



(Catch up!)

Review Exam I

Are you
up to date
in your reading
of Purcell?
Catch up!
(read through Sect. 5.7)

If caught up in Purcell,
supplement your understanding
by consulting
The Feynman Lectures on Physics
Volume 2
,
by Richard P. Feynman, R. B. Leighton, and
M. Sands
(Addison-Wesley, but openly available online)

Feb. 19


Transmitting
News of the World
to Distant Corners

Purcell thru Sect. 5.8

Feb. 21


Momentum
of
the fields


Purcell thru Ch 5 Summary

Context for Fig. 5.7 (p. 243):

IWU Physics student Joe Richards, with collaborators Yoshi Arita and Kishan Dholakia,
was able to create what was (at the time) the world's fastest spun man-made object.
That record has since been surpassed, but you might ask,
"What's the ultimate limit?":


...You might recall that electrons are NOT man-made objects:



HW Set# 5b Due Monday, Mar. 3:
Purcell Ch 6: Problem 6.2;
Exercises 6.29, 6.30, 6.31, 6.33, 6.42



HW Set# 6 Due Monday, Mar. 10:
Purcell Ch 7:
Exercises 7.35, 7.42, 7.43

Feb. 24


Properties of B
AND of the
Vector Potential

Open discussion
of
vector potential,
leading towards
your plans for
World Domination, er, ...um,
I mean
your plan for
doing something
potentially good!

Purcell thru Sect. 6.1

Feb. 26


Magnetostatics
Summary

Gabe says to PLAY!
with
interactive tutorials
from the
National Magnet Lab

Purcell
thru Sect. 6.3,
followed by
Piazza Note @52

Feb. 28


EXAMINATION II
covers
through
Chapter 5
of Purcell

Purcell thru Sect. 6.6

You've gotta watch this prototype Mag Lev system:

Here's another example of inductive levitation:


As we increase the rate of change, induced currents can melt boules of metal,
And the levitation avoids contamination by eliminating any crucible:

(Metallic glass can be made using this method,
by "splat cooling" onto a rotating wheel)

Weekly Goal: appreciate the Aharanov-Bohm effect



HW Set# 5b
Due Monday, Mar. 3:
Purcell Ch 6:
Problem 6.2
Exercises:
6.29, 6.30, 6.31, 6.33, 6.42


HW Set# 6
Due Monday, Mar. 17:
Purcell Ch 7:
Exercises 7.35, 7.42, 7.43

Mar. 3

Discussion of
outstanding
issues

Semon & Taylor

Purcell Ch 6
(remainder)

Mar. 5

Segue from statics
to dynamics:
Explore
many
MIT Teal Visualizations

Purcell thru Sect. 7.4

Mar. 7

Using the words
"Induce"
and
"Induction"
in many ways

Purcell thru Sect. 7.9

.

It all comes back to fundamental principles:

Weekly Goal: appreciate your PHYS 106 text



HW Set# 6 Due Monday, Mar. 17:
Purcell Ch 7:
Exercises 7.35, 7.42, 7.43



HW Set# 7a
Due Monday, Mar. 24:
Purcell Ch 8
Problems:
8.1, 8.2, 8.3, 8.4

Mar. 17


Magnetic Field Energy


Purcell Ch7
(remainder)

Mar. 19


The AC
Skin Effect

Spend time on problem solving:
Catch up,
as needed!

Piazza Notes @66
and
@70

Mar. 21


Damped Harmonic Oscillators
and
Q
("Quality Factor")

Read thru
Purcell Sect 8.1
(You have the Power!)

Here's a way to show off:
...start at the 9:20 timestamp on this video


Why is light slower in glass or water?
(From the Sixty Symbols YouTube channel)

Weekly Goal: spend serious time on problem solving!



HW Set# 7a
Due Monday, Mar. 24:
Purcell Ch 8
Problems:
8.1, 8.2, 8.3, 8.4


HW Set# 7b
Due Friday, Mar. 28:
Purcell Ch 8: Exercises
8.26, 8.27, 8.32, 8.34

Mar. 24


AC Circuits
(Pronounced as
"Ack! Circuits!!")
...made a bit easier?

Purcell thru Sect 8.5

Mar. 26


In-class,
at-the-board,
discussion of
AC circuit
problems

Purcell thru Sect. 8.6

Mar. 28


Example application
connecting
Admittance & Impedance & Power & Energy
(Oh my!)

Purcell thru Ch 8 Summary

The rotating vectors at bottom left are called PHASORS;
they keep track of where we are in each cycle, for I and V.
Try switching from a resistor to a capacitor or an inductor:

Weekly Goal: spend serious time on problem solving!



HW Set# 8a Due Friday, Apr. 4:
Purcell Ch 9:
Problems 9.11, 9.12


(Start early on next set)

Mar. 31


Maxwell's Wave Equation

Let
there
be
light!

Purcell thru
Sect. 9.4

Apr. 2


"Follow the money!"
Energy
and
Momentum

Read
Feynman Lectures
Vol. II: Ch 27
and think
about Causality
("Who's on First?")

Purcell thru
Ch 9 Summary

Apr. 4


A Polarizing Lecture
(to be sure)

Purcell thru
Sect. 10.6

Fourier's Trick: breaking complexity into simple waves

(Videos from the Sixty Symbols YouTube channel take time,
but taking Physics is rewiring your brain!)

This weekend, try everything you can with this applet:

Weekly Goal: appreciate that all models have a limited range of applicability
(That said, what we've discussed is self consistent)



HW Set# 8b
Due Monday, Apr. 14:
Purcell Problem 10.2
Exercises 10.17, 10.28, 10.35, 10.36

Apr. 7


Polarization
as a
Feedback Problem
&
Constitutive Relations

Purcell thru
Ch 10 Summary

Apr. 9


Review!

Review!

Apr. 11


EXAM III
Thru Ch 8

Review!

How to see without glasses:


Weekly Goal:
Share something wonderful
on our Discussion page



HW Set# 8b
Due Monday, Apr. 14:
Purcell Problem 10.2
Exercises 10.17, 10.28, 10.35, 10.36


HW Set# 9 Due Friday, Apr. 18:

Purcell Ch 11: Problems 11.1, 11.4; Exercises 11.16, 11.22, 11.30

Apr. 14


Magnetic
Matters

(Is your
Intro Physics
text
helpful
on this?)

Purcell thru Sect. 11.4

Apr. 16


WHAT
THE
H
?

In-class,
at-the-board,
discussion
of
HW
problems

Purcell thru Sect. 11.8

Apr. 18


Polarization,
Magnetization
&
Boundary Conditions!

Purcell thru
Ch 11
Summary

Every rare earth metal halide lamp you come across, a cut goes to the Anderson Physical Laboratories,
founded by IWU Physics grad Dr. Scott Anderson. For example, his lamps illuminate the Statue of Liberty, and many major sports facilities.

Because he helped fund this building, room C101 of CNS is the Anderson Auditorium.
Each year, we name an IWU Scott Anderson Scholar in Physics.


Sometimes, information carried by light appears to be lost:

HW Set# 10
EXTRA CREDIT ONLY
Purcell Append. H: Exercises H.1, H.2, H.3
(Due at Final Exam)

Apr. 21


In-class,
at-the-board,
discussion
of
HW
problems

Purcell Append. J

Apr. 23


Conceptual
REVIEW


Final Exam
covers
in-class
discussions
(through
Ch 11)

Review!

Apr. 25


Zen
Express!

Review!

Remember, all information is physical:

I'm interested in ways to recover
information that appears to be dissipated during transmission.

If we are clever enough, there can be ways of recovering "lost" information:

Wanna play?

FINAL EXAMINATION: Tues., 29 April, 1:15-3:15pm

...You might be interested in discussing articles we've produced on these topics:

Your Dungeon Master: Gabe Spalding

Office: CNS room C006B.
Tel: 556-3004.
Electronic communication: gspaldin@iwu.edu