Physics For Engineers and
Scientists II
Principles of Electricity and Magnetism
Dr. Jeffrey B. Bindell
Fall 2005
General Information
Instructor: Dr. Jeffrey Bindell
Schedule M,W,F 10:30 AM to 11:20 AM Room 359
Phone 407-823-4194
E-mail: bindell@physics.ucf.edu
Website: www.physics.ucf.edu/~physics
OFFICE HOURS: M,W,F 8:30-10:00 AM
MAP-417
Books and Stuff
Textbook Fundamentals of Physics
Halliday, Resnick and Walker, Seventh Edition, Wiley
WebAssign Login
Keep in Mind
Grades
Item
Weight
Mid Semester Examinations
3
Final Examination
2
Homework
2
In Class Quizzes
1
Homework
It is important to notice that homework counts for 25% of
your grade. Homeworks will be based on WebAssign.
Although “extensions” will be available, valid reasons should
be offered at the time or he request.
There will be approximately two assignments per week. The
first will be due on Monday and will require that some advance
reading be done. These questions will be multiple choice. This
will assure that you are properly prepared for the lecture
and/or demonstration for the upcoming week. The second will
be a series of more difficult problems and will generally be due
on Fridays.
WebAssign Startup
Digits of your PID
ihatephysics
Be sure to change your
password as soon as
possible to avoid someone
else doing your homework!
No Curve
SCORE
85-100
75-84
60-74
50-59
Less than 50
GRADE
A
B
C
D
F
Approximate Exam Schedule
EXAM
NUMBER
1
2
4
FINAL EXAM
DATE
9-23 (Fri)
10-21 (Fri)
11-23 (Wed)
Check UCF Cal.
ratemyprofessors.com
Completely unforgiving. Unhelpful office hours from which
you leave more confused and with more questions than
you came with. Seems to have no time for students, will
not listen to any excuse, reasonable or not. Do not be 1
minute late on quiz day. Family emergency, car trouble=
unforgivable sin
Very difficult. Not in a tough way, but in an unhelpful
way. Does not go over problems and his office hours
are not helpful at all. You leave just as confused. Does
not go over tests.
ratemyprofessors.com
Waiting for grades to come in. Have no idea if I passes or
failed. Tests are UNFAIR, GRADING IS UNFAIR. I didn't
miss more than a day of class. This class is an experiment
and I don't like being the guinea pig when my GPA is on the
line. Something better give or EVERYONE in the class will
fail.
ratemyprofessors.com
This class sucks, but Bindell makes it doable. He
answers ?'s, speaks clearly, and is pretty funny too.
Fair tests and decent curves for the final grade. Do
your webassign and make yourself known, you will
pass this class...
Very hard class.Tests consist of 1 homework
problem and 2 unseen problems, one easy, one
hard.If you go to office hours(if you can get him on
a day he's there)he will usually give you extra
points on tests that TA's graded unfairly. He also
curves the grades a lot.I was looking at a C and
made an A
Comments from Surveys (abbreviated)
 Powerpoint lectures suck! Too much, too fast.
Too fast.
 Do more problems in class and not as much
theory.
 Miss too many office hours.
Last semester was bad.
I will still miss some of them.
 Missed too many classes.
Indeed I did.
The Facts …
Last Semesters Final Grades
Percent of Class
40
30
20
10
A
B
C
D
F
0
Grade
F includes people who forgot to withdraw and just stopped attending.
What I learned:
Students don’t like lectures, especially
PowerPoint.
Students don’t like WebAssign
Some problems too hard
Some problems are not coded correctly by WA.
Students don’t like tests unless they are
easy.
They’re NOT!
Course is hard, why would tests be easy???
My gripes ….
Students study at the last minute.
Students have big holes in their math
skills:
Interpreting Graphs.
Using Calculus.
Students come to my office expecting me
to solve their homework problems.
I will always help … I will not give you the
answers!
Work on the problems before you come for
help.
Feedback Based Approach
More demos when possible.
More problems in class
Minimize PowerPoint.
Last semesters PP notes are on my website.
Watch out for some errors that were not
corrected on the slides.
This approach requires that class does its
reading beforehand.
How to get an A.
 Weekend
Read next weeks material.
Complete short answer assignment before class time.
 During Week
Work the long problems from WebAssign
Different problems will be worked in class.
Ask Questions
 Fridays will usually be Quiz day unless you want
them on Mondays. Some will be “strange”.
 All exams will be on Fridays (except for the
Wednesday before Thanksgiving)
Studying helps!!
What’s Up?????
Today
Introductory Comments
Electricity (Read First Chapter on Charge)
Wednesday
Electrical Forces and Problems
Friday
Quiz
Finish the Chapter
Basics of Electrical
Charge
Week-1
Probable First Observation of Charge
Don’t Mess With Mother Nature
St. Elmo’s Fire
A Quick Experiment
Idiot!
If lightening had actually traveled down the kite
string, old Ben Franklin would have been toast!
History
600 BC
Thales of Miletos rubs amber (electron in
Greek) with cat fur and uses it to pick up
feathers.
Important questions:
Why was he doing this?
Didn’t he have a job??
What happened to the skinned cat?
Amber
Million years ago large stands of forests in
some parts of the world began to seep
globs of sticky resin! This aromatic resin
oozed down the sides of trees, as well as
filling internal fissures, trapping debris,
such as seeds, leaves, feathers and
insects. As geologic time progressed the
forests were buried and the resin
hardened into a soft, warm, golden gem,
known as amber. Amber is the fossilized
resin of ancient trees which forms
through a natural polymerization of the
original organic compounds. Most of the
world's amber is in the range of 30-90
million years old.
Rubbings
Photo
Effect of Charge
What’s Going On?
All of these effects involve rubbing two
surfaces together.
Or pulling two surfaces apart.
Something is on each of these objects.
We call this “something” CHARGE.
We have also observed that there must
be TWO kinds of charge.
Call these two types
positive (+)
negative(-)
We “define” the charge that winds up on
the rubber rod when rubbed by the dead
cat to be NEGATIVE.
The charge on the glass rod or the dead
cat is defined as POSITIVE.
What happens when two
surfaces touch or rub?
Bonding!
Example - Tape
The Triboelectric Series
When two of the following materials are rubbed together under
ordinary circumstances, the top listed material becomes
positively charged and the lower listed material becomes
negatively charged.
No! No!
No! No!
MORE POSITIVE
rabbit's fur
glass
mica
nylon
wool
cat's fur
silk
paper
cotton
wood
acrylic
cellophane tape
polystyrene
polyethylene
rubber balloon
saran wrap
MORE NEGATIVE
Summary - Rubbings
What have we found?
 There are TWO types of charge.
Positive
Negative
 Like Charges Attract
 Un-Like charges repel
 The force between charges increases as they
are brought closer together.
 This charge separation results from chemical
bonds which are severe in the pocess.
Forces Between Charges
Q1
Q2
Attract
+
+
+
-
X
-
+
X
-
-
Repel
X
X
Types of Materials
 Insulators
Holds a charge
 Conductors
Allows charge to easily move (current)
 Semiconductors (Si, Ge, C …)
Somewhere in the middle, very temperature and
impurity sensitive.
Used for transistors and optical devices such as LEDs
and Semiconductor Lasers.
 Semi-Metals
Don’t ask!
The Electroscope