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ADVANCED PLACEMENT PHYSICS C (Electricity and Magnetism)
Michael Crofton (Spring Lake Park High School)
Overview
Advanced Placement Physics C, commonly known as AP-C Physics, is similar to a college preengineering physics course. To be honest, it is more difficult than most college courses of that level.
This AP-C course is a physics course that uses calculus in many of the problems students are asked
to solve. This course will prepare students for two tests at the end of the year. One test covers
mechanics, and the other covers electricity and magnetism (E&M). Students can take either or both
tests on test day. To get through this much material, we will need to cover about a chapter a week.
We will move very fast through the material that we covered last year. We want to be done with the
Mechanics material by early January, and finish electromagnetism in April. Hopefully we will have 3
weeks for review.
Goals for the course:
Students will come out of this course with an excellent understanding of freshman college calculus
based physics. They will understand it at a high level both conceptually and in problem solving.
Students will also be able to design, perform and analyze laboratory investigations. Students will earn
a minimum of a 3 on the Level C, AP Physics exam on electricity and magnetism. (I expect all of my
students to earn a 4 or 5.) A score of 5 will earn college credit at almost any college or university. A
score of 3 will earn credit at many, and a 4 will earn credit at most.
Prerequisites for the course
To register for AP Physics each student must have previously taken a year of physics. For the best
preparation, it is preferred that the first course was Accelerated Physics, although students with a
year of General Physics are able to be successful if they put in extra time. To take the AP-C
course, at the minimum, students should have completed Pre-calculus and be taking Calculus
concurrently. If you are in the E&M class you will have just finished an AP course in Mechanics.
Tests
There will be two tests per unit. One test will be 35 multiple choice questions, and the other will be
three large free response problems. This is the format under which the official AP test will be taken.
The multiple choice tests will have a large number of conceptual questions however there are
problems to solve also. To help acclimate students to taking the timed AP tests in the spring,
students will be allowed 45 minutes for each test. While each test will have questions from the unit
we are in, problems from other areas we have covered are open game for any test. When grades are
calculated at the end of the tri, the worst test of the trimester will be dropped. (By the way, there are
short-answer conceptual questions on the free response tests also.)
Textbook and Materials
We use Fundamentals of Physics by Halliday, Resnick and Walker (referred to as HRW) as the
primary text for the course. Our text is the 4th Edition, copyright 1993 by John Wiley and Sons. In the
last three years I have become fascinated with the textbook, Matter and Interactions: Volume 2,
Electrical and Magnetic Interactions by Ruth Chabay and Bruce Sherwood. This textbook is
published by John Wiley and Sons, copyright 2007. This textbook is written to help understand
physics at the microscopic level. Using this text as a supplemental text allows me to help students
understand why some of the macro phenomena we study occur. I like the way it also takes the basic
principles of physics along with reasonable approximations to create estimates of the phenomena
being studied. For example, in one exercise we use the repulsion of two charged pieces of
transparent tape to estimate the fraction of atoms that gained or lost an electron when the tape
became charged. Many of the labs that we do are hands on labs from Dr. Sherwood’s course. Some
units will use also use supplementary materials created by your teacher.
Laboratory
My philosophy in teaching physics is that whenever possible I want my students to see physics in
action before we talk about it. I use an inquiry based method of teaching where students investigate
a phenomena or relationship with hands on manipulation, then we talk theory. My goal is to spend at
least 30% of the time doing hands on work in the laboratory. At times this may require students to do
take home labs. Unlike the study of mechanics that preceded this course, almost everything covered
in the E and M course will be new material. Your first year course only covered DC circuits which is a
portion of one unit this course. Electricity and magnetism are much more abstract than mechanics.
To help build your understanding of electricity and magnetism there will be many short laboratories.
Students will be given a hands on task to perform with various equipment and materials. As they
work, students will be asked to create diagrams and answer questions that probe their understanding
of what they did or saw. When everyone is done students will present their answers to the class on
whiteboards and explain their reasoning. There will also be some investigations like you did last year
where you design an experiment to determine the relationship of variables. You will take data and
graphically analyze it to determine these relationships. After you have shared your findings in
whiteboard presentations you will create a formal write-up for this type of lab
Due to the nature of what is being studied, some investigations will be done using software. In units
that do not lend themselves to taking data, such as electric fields and charged particles in magnetic
fields, students will write programs in VPython programming language to visually model on the
computer the concepts they are studying. Physics Academics software program EM Fields is also
used to help model that which is difficult to measure.
Electricity and Magnetism
Unit 1: Electric Charge and the Electric Field
Chapters 23 and 24 in HRW Textbook
(Approximately 2 weeks)
Major topics:
 Methods of producing electrostatic charge
 Behavior of insulators and conductors
 Polarization and Induction
 Electric force and Coulombs Law
 Superposition
 The electric field due to a point charge
 The electric field of a dipole (along dipole axis and along a perpendicular axis)
 Using superposition to determine the net electric field due to more than one charge
 Determining electric field vectors
 Drawing electric field lines
 Determining the electric field due to a collection of point charges (Integral calculus)
 Rings of charge (at any location on the axis of the ring)
 Curves (at center of curvature)
 Lines of charge (at the end and at a location near the center)
 A charged disk (at a location on the axis)
 Behavior of a point charge in an electric field
Labs
Sticky tape lab (Hands on lab using transparent tape to study the behavior of charged and uncharged
insulators and conductors. This lab is done as a take home lab.)
Electrophorus lab (Hands on lab that uses an electrophorus and a neon bulb to gain an understanding
of polarization and induction. Lab takes one class period.)
Coulombs Law lab (Determining the relationship of the electric force and the separation distance of
the charges. A film has been made of two charged spheres repelling. Data is gathered by measuring
on a computer monitor. Data is graphed and linearized to derive the relationship. Lab takes one class
period.)
Determining the charge on a piece of tape (A hands on lab where students use charged transparent
tape, Coulomb’s Law and some estimations to determine the approximate charge the tape. They also
determine the approximate fraction of the atoms on the tape that gained or lost electrons. Lab is
done as a take home lab.)
Investigation of electric fields (A virtual lab that uses EM Field software. Lab takes one class period.)
Practice problems in HRW
Chapter 23: 6, 8, 9, 10, 13, 14, 19, 21
Chapter 24: 3, 4, 8, 10, 13, 15, 18, 21, 32, 33, 34, 39, 40, 44, 47, 51, 52, 56
Unit 2: Gauss’s Law and Electric Potential
Chapters 25 and 26 in HRW Textbook
(Approximately 2.5 weeks)
Major topics:
 The concept of electric flux
 Gauss’s Law
 Determining the charge enclosed by a surface using Gauss’s Law
 Using Gauss’s Law to solve for the electric field for the following geometries
 Point charges
 Spheres – conducting and insulating, solid and hollow
 Solid and hollow cylinders
 Sheets
 Insulating cylinders and spheres with non-uniform charge density
 Review the concept of potential energy and define electrical potential energy
 Defining electric potential and change in electric potential (delta V)
 Sign of delta V and the electric field
 Potential at one location
 Equipotential surfaces and lines
 Independence of path and delta V
 Round trip delta V is always zero
 Potential due to a point charge and a small group of point charges
 Using algebra to solve for change in potential for constant electric fields
 Using calculus to solve for the change in potential for fields that are not uniform
 Point charges or spheres
 Rings of charge
 Charged cylinders
 The electric field strength as the negative of the rate of change of potential with respect to
position
 Using calculus to determine E, E is –dV/dx
 Potential energy due to a small group of point charges
Labs
Topographic map activity (A hands on activity that uses geology materials to create a topographic
map of a volcano. Lab takes one half of a period.)
Mapping electric potential (A hands on lab that uses conductors in baking dishes with 2 cm of water.
Data is put into a spreadsheet and graphed in two and three dimensional “landscape maps”. Lab
takes one class period.)
Exploring electric potential activity (Uses EM Field software, the activity takes one class period.)
Measuring potential differences (Hands on activity with a voltmeter, wires, bulbs and a battery. The
lab takes one class period.)
Practice problems in HRW
Chapter 25: 2, 4, 5, 8, 9, 15, 18, 19, 23, 24, 25, 27, 31, 34, 35, 36, 38, 43, 47, 48, 49, 51, 52, 53, 60,
61
Chapter 26: 2, 3, 4, 5, 7, 8, 10, 11, 15, 17, 20, 21, 23, 26, 34, 35, 37, 38, 39, 42, 43, 46, 51, 53, 56,
58, 60, 61, 66, 68, 70, 73, 74, 79, 81
Unit 3: Capacitors and DC Circuits
Chapters 27, 28, and 29 in HRW Textbook
(Approximately 2.5 weeks)
Major topics:
 Charging and discharging capacitors at the microscopic level along with fringe fields
 The definition of capacitance
 Energy in capacitors
 Deriving capacitance using summation of E dot ds and the definition of capacitance
 Parallel plate capacitors
 Cylindrical capacitors
 Spherical capacitors
 Capacitors in series and parallel
 Capacitors with dielectrics
 A microscopic view of electric circuits
 The surface charge model for electric fields in a circuit
 The initial transient in a circuit
 Energy conservation in circuits (also known as the Kirchoff’s Loop rule)
 The current junction rule for circuits
 Ohmic and non-Ohmic resistors
 Ohm’s Law
 Series and parallel resistor
 Single and multiloop circuits
 Power in circuits
 Real batteries and internal resistance
 Resistor-Capacitor circuits (RC circuits)
 Charging and discharge cycles (First exposure to differential equations)
 The time constant for an RC circuit
Labs
Energy in a capacitor (Hands on lab that uses 25,000 to 100,000 microfarad capacitors. They are
charged with batteries and discharged through a Genecon to determine the relationship between
energy and potential difference across the charged capacitor. Lab takes one class period.)
The transient in connecting a circuit (A short hands on lab to show the transient in setting up a steady
state circuit. Lab takes one half of a class period.)
Nichrome wire lab (A short hands on lab to get the relationship between the length of a conductor, the
cross sectional area of a conductor, the electric field in a conductor and the current the conductor
carries. Lab takes one class period.)
Time constants in RC circuits (Hands on lab with computer interface. Graph charge and discharge
cycles and calculate the time constant using three methods. Lab takes two class periods.)
* In their physics class last year students did an Ohm’s Law lab and a big circuit lab that we are not
repeating.
Practice problems in HRW
Chapter 27: 4, 5, 7, 8, 10, 16, 17, 18, 19, 20, 22, 25, 28, 30, 32, 36, 37, 42, 44, 52, 55, 57, 59, 61, 62,
66, 67
Chapter 29: 1, 5, 6, 8, 11, 15, 16, 24, 27, 30, 33, 37, 39, 41, 45, 47, 49, 65, 66, 67, 68, 71, 72, 77, 78
Unit 4: Magnetism
Chapters 30 and 31 in HRW Textbook
(Approximately 2 weeks)
Major topics:
 Detecting magnetic fields
 Magnetic field vectors for lines for wires
 Dipole fields of a bar magnet and a coil or solenoid
 Biot-Savart Law for a single moving charge
 Magnetic force on moving charge
 Biot-Savart Law for currents
 Magnetic force on a current carrying wire
 The principle of an electric motor
 Using Ampere’s Law to determine the magnetic field for the following geometries
 A cylinder
 A solenoid
 A toroid
 Magnetic force as an inward force
 Combination of magnetic and electric fields (Lorenz force)
 The Hall effect
 Using the Hall effect to determine sign of charge carrier
 The principles behind mass spectrometers and cyclotrons
Labs
Magnetic Field around a current carrying wire (Hands on qualitative investigation with a current
bearing vertical wire and a compass. This lab and the one below are done in the same class period.)
Magnetic field around a current carrying coil (A short hands on lab to show that the magnetic field for
a coil resembles that of a dipole.)
Strength of the Magnetic field around a current carrying wire (The purpose is to determine the
relationship of the strength of the magnetic field and the distance from the wire. Data is taken and
analyzed graphically by students. Lab takes one class period.)
Magnetic balance lab (A hands on lab where students determine the relationships of the length of the
wire and the magnetic force on a current carrying wire, the current and the magnetic force on a
current carrying wire and the magnetic field strength and the force on a current carrying wire.
Students gather data and analyze it graphically to determine the relationships. Lab takes one class
period.)
Magnetic force on a charge particle (A virtual lab where students write a Vpython program to visually
model the path of a particle moving perpendicular to a magnetic field. They then modify to program to
change the variables of magnetic field strength, velocity of the charge, sign of the charge and angle of
the velocity. They will see the effect on the radius of the circle and the direction of the motion.
Program is written outside of class time.)
Practice problems in HRW
Chapter 30: 5, 11, 12, 19, 22, 25, 43, 44, 46, 48, 52, 53, 54, 61, 62, 65
Teacher prepared worksheets on magnetic fields and magnetic forces
Chapter 31: 1, 3, 10, 11, 27, 38, 41, 42, 43, 44, 48, 53, 56, 60, 61
Unit 5: Faraday’s Law and Induction
Chapters 32, 33 and a bit of 37 in HRW Textbook
(Approximately 2 weeks)
Major topics:
 Motional EMF
 Changing magnetic fields producing “curly” electric fields
 The concept of magnetic flux
 Faraday’s Law and the concept of induced EMF
 Problem solving using average rate of change of flux
 Problem solving using both differentiation and integration to solve for induced EMF
 Lenz’s Law
 The relationship between motional EMF and Faraday’s Law
 The principle of a generator
 Definition of Inductance
 Deriving inductance using Ampere’s Law and the definition of inductance
 For solenoids
 For toroids
 Energy in an Inductor
 Self Inductance
 Gauss’s law of magnetism
 Resistor-Inductor circuits (RL circuits)
 Charging and discharge cycles (Another exposure to differential equations)
 The time constant for an RL circuit
 Maxwell’s equations
 Displacement current
Labs
Faradays Law conceptual lab (A hands on lab with a galvanometer, solenoid, power supply and a bar
magnet used to help students determine the direction of the induced EMF. The lab takes one class
period.)
Dropping a magnet through a coil (A teacher led investigation where students predict the shape of a
graph produced when a magnet is dropped through a big coil hooked to voltage probes. Takes a
third of a class period.)
Faradays Law quantitative (A hands on lab with a large solenoid, a small solenoid, and a function
generator to study the induced EMF in the small coil due to a changing current in the large solenoid.
The lab takes a class period.)
Practice problems in HRW
Chapter 32: Conceptual questions - 10, 11, 12, 13, 14, 19, 20, 21
Problems - 4, 5, 6, 8, 9, 14, 15, 24, 28, 30, 34, 35, 36, 37, 40, 41, 42, 43, 48, 50
Teacher prepared worksheets on induced and motional EMF
Chapter 33: 1, 2, 11, 12, 16, 17, 18, 21, 23, 24, 25, 26, 27, 31, 32, 34, 35