1. Exam Information In class next Friday, ~1 hr.
15 multiple-choice problems
Half “conceptual,” half calculation
Closed book, one page of notes
One 8 ½” x 11” sheet of paper
May contain whatever information you think might help
Bring a calculator
Cannot connect to internet or contain text book
e.g. not phone, computer, iPad, etc.

2. Please be aware:
Provided—If you something necessary missing, let me know
Constants
e.g. ε0, μ0, etc.
Formulas not from course
e.g. volume of a sphere
Not provided—If you want them, put them on your note sheet
Unit definitions
e.g. V = J / C
Formulas from course

3. What NOT to study
Midterm Exam 2012

4. Topics NOT on the exam
You should be familiar with the following material, but not exam questions will specifically test for knowledge of it
Anything not in the requested reading, including the following material from lectures
Electric energy density (18.8)
Ammeters and Voltmeters (19.6)
Temperature dependence of resistance (19.10)
Earth’s magnetic field and cosmic rays (20.9)
Applications of induction (21.7)
Impedance in AC circuits (22.7)
Transformers (22.9)

5. Topics NOT on the exam
You should be familiar with the following material, but not exam questions will specifically test for knowledge of it
These specific topics from lecture
Dielectrics
Real batteries
Magnetic moment
Hall effect
Chapter 23 (lucky!)

6. Midterm Review
Midterm Exam 2012

7. WARNING! This review is NOT comprehensive
It should serve as a reminder of major topics covered by the course
It will not review all topics covered
Be sure to review all lecture slides, assigned reading, homework, and recitation notes

8. Charge and Electric Force
Electric charge comes in two types:
+ and –
Charges exert a force on other charges
Likes repel, opposites attract
Force is vector (obeys superposition)
Magnitude given by Coulomb’s law:
Directional
(doesn’t change magnitude)
Chapter 17

9. Electric Fields and Field Lines
Electric field quantifies the “force potential” of one charge
Divide out second charge
Field lines represent electric field graphically
Lines begin on + and end on –
Chapter 17

10. Flux and Gauss’s Law Gauss’s law can help find electric field
Useful for simple geometries
Point, sphere, line, barrel, sheet,
Relates net electric flux to enclosed charge
Flux entering is negative, flux exiting is positive
Electric Flux is defined as:
Magnetic flux is similar
Flux is a scalar quantity
Chapter 17

11. Potential and Potential Energy
Potential energy measures the energy required to move a charge to its present position
Usually referenced from infinity
Only net displacement along direction of force matters
Potential (or voltage) quantifies “energy potential” of one charge
Chapter 18

12. Equipotential Surfaces and Electric Field Lines
Equipotential surfaces represent potentials graphically
Equipotentials are 3D
Connect points of same potential
Largest positive magnitude near +
Largest negative magnitude near –
Equipotentials are everywhere perpendicular to electric field lines
Chapter 18

13. Summary Vector Scalar 2-particle Force: (N) Potential Energy: (J)
1-particle
Electric Field: (N/C)
Potential: (V)

14. Conductors and Insulators
Conductors and Insulators (non-conductors):
Conductors (metals)
Charge moves around
Excess charge is all on the surface
E field inside is zero
Entire object can be charged
Insulators
No conduction (movement) of charge
Extra charge stays where it is placed

15. Polarization and Induction
Electric fields can cause charges to align, causing material to polarize
Occurs in both conductors and insulators
Used to induce a net charge in a region or across an entire object

16. Magnetic Fields and Forces
Created by moving charges
Form loops from north to south
Shape—wire, loop, solenoid, etc.
Right-hand rule 1
Magnetic forces
Perpendicular to field
Right-hand rule 2
Particle, current wire, current loop
Mass spectrometer, Bubble Chamber
Torque

17. Right-Hand Rule
Right-hand Rule 1 gives direction of Magnetic Field due to current
Right-hand Rule 2 gives direction of Force on a moving positive charge
Section 20.1

18. Magnetic Induction Faraday’s Law Lenz’s Law
“A changing magnetic flux induces a voltage”
Lenz’s Law
“the magnetic field produced by an induced current always opposes any changes in the magnetic flux”

19. Resistors, Capacitors, and Inductors
Series vs. Parallel
Series—the same current
Parallel—the same potential change across each component
Resistors
Ohm’s Law:
Resistance depends on how resistor is constructed
For resistors in series
For resistors in parallel

20. Resistors, Capacitors, and Inductors
Capacitance is defined as
Capacitance depends on how capacitor is constructed
For capacitors in series
For capacitors in parallel

21. Resistors, Capacitors, and Inductors
Inductance is defined as
Inductance depends on how inductor is constructed
For inductors in series
For inductors in parallel

22. Circuits Current Kirchhoff’s Rules
Loop Rule—the change in potential energy of a charge as it travels around a complete circuit loop must be zero
Junction Rule—the amount of current entering a junction much be equal to the current leaving it

23. DC and AC circuits DC Circuits AC Circuits
Voltage at source is constant
RL circuits
RC circuits
AC Circuits
Voltage at source oscillates
I and V in AC circuits
RMS, Average, Instantaneous
LRC circuits
Resonance