- Current
- Ohm's Law
- Ohm's Law for Insulators and Conductors
- Ohm's Law and Temperature
- Demonstration: Breakdown of Ohm's Law
- Resistors in Series and in Parallel
- Demonstration: Increasing the Conductivity of Air
- Demonstration: Increasing the Conductivity of Water
- Resistance in Your Shoes
- Power Supply
- Batteries in Circuits
- Demonstration: Batteries in Series
- Power
- Power in a Resistor
- Power in a Battery
- Demonstration: Shorting a Car Battery
- Ohm's Law and Kirchhoff's Rules
- High Voltage Power Lines
- Current in DC Circuits
- Circuit Conventions
- Equivalent Resistance

- Kirchoff's Circuit Rules
- Measuring Voltage and Current
- Electromotive Force
- More on Solving Circuits
- Current and Current Density
- Ohm's Law, Resistance, and Resitivity
- Typical Values of Resistivity
- Resistance of a Cable
- Drift Velocity in Sea Water
- Resistance of a Hollow Cylinder
- Conceptual Questions on Resistance and Power
- Current of a Whirling Charge
- Ohm's Law for a Radiant Heater
- Drift Speed of Electrons in Copper Wire
- Current Sheets
- Resistance of a Drawn Out Wire
- Ohm's Law for a Lightbulb
- Resistivity and Resistance
- Voltage in Power Lines
- 3-Resistor Circuit
- Bulbs in a Circuit

Definition, with example of calculating the drift velocity current for a copper wire.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 9 (0:00 - 6:52)
Current

Statement of Ohm's Law with definitions of conductivity, resistance, and resistivity.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 9 (6:52 - 13:14)
Ohm's Law

Comparison of the properties of good conductors and good insulators.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 9 (13:14 - 17:13)
Ohm's Law for Insulators and Conductors

Explanation that temperature can cause Ohm's Law to break down. Includes a demonstration of Ohm's Law holding for one resistor and not for another.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 9 (17:13 - 23:09)
Ohm's Law and Temperature

Ohm's Law failing to hold for a light bulb with a resistance that varies with temperature.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 9 (23:09 - 27:10)
Demonstration: Breakdown of Ohm's Law

Definition and comparison of values for resistance, current, and voltage.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 9 (27:10 - 32:38)
Resistors in Series and in Parallel

Using a candle to increase the conductivity of air near an electroscope.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 9 (32:38 - 36:53)
Demonstration: Increasing the Conductivity of Air

Using salt to increase the conductivity of water and light a bulb.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 9 (36:53 - 43:08)
Demonstration: Increasing the Conductivity of Water

Calculation of resistance between body and Earth through a pair of shoes, including a demonstration that this resistance is not high enough to keep charge from flowing.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 9 (43:08 - 49:16)
Resistance in Your Shoes

Definition and explanation of how a battery works, with examples.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 10 (0:00 - 7:16)
Power Supply

Symbol for a battery in a circuit diagram, definition of electromotive force and internal resistance.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 10 (7:16 - 10:50)
Batteries in Circuits

Connecting two batteries in series to demonstrate that the electromotive force doubles.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 10 (10:50 - 15:20)
Demonstration: Batteries in Series

Derivation of the equation for power P=IV, including definition of Watts as unit of power.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 10 (15:20 - 18:14)
Power

Finding the power consumed by a resistor, with examples including light bulbs, heaters, and the human body.

8.02 Electricity and Magnetism, Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 10 (18:14 - 23:57)
Power in a Resistor

Finding the power supplied by a battery, with a demonstration of a 9 V battery being shorted out.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 10 (23:57 - 28:30)
Power in a Battery

Showing the large current and power supplied by a car battery when it is shorted out.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 10 (28:30 - 31:18)
Demonstration: Shorting a Car Battery

Finding currents and power in a circuit of batteries and resistors.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 12 (32:47 - 44:14)
Ohm's Law and Kirchhoff's Rules

Discussion of the advantages of transporting electric energy at high voltages to minimize power loss. Calculation of the maximum voltage possible without causing corona discharge, including a slide of corona discharge on a power line during a storm.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Watch video clip from Lecture 14 (20:39 - 32:58)
High Voltage Power Lines

Definition of current and current density; microscopic and macroscopic Ohm's Law.

8.02

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

Circuit element symbols; sign conventions; drawing resistors and capacitors.

8.02

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

Rules governing resistors in series and parallel; how to calculate equivalent resistance in each.

8.02

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

Illustration of Kirchoff's Circuit Rules and method for solving a circuit; includes discussion of internal resistance in batteries.

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

How to measure voltage, current, and resistance in a circuit.

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

Definition from E-field; car batteries; direction of current flow.

8.022

*Electricity and Magnetism,*Fall 2004

Prof. Gabriella Sciolla

**Course Material Related to This Topic:**

Using Kirchhoff's rules to solve complex circuits; internal resistance and power dissipation.

8.022

*Electricity and Magnetism,*Fall 2004

Prof. Gabriella Sciolla

**Course Material Related to This Topic:**

Definition of macroscopic current and microscopic current density.

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

- Read chapter 6, pages 2–4 of online textbook

Derivation of macroscopic Ohm's Law (V = IR) from microscopic; introduction of resistance, resistivity and conductivity, including temperature effect on resistivity.

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

- Read chapter 6, pages 4–7 of online textbook

A table of values for resistivity and conductivity of several materials.

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

- Read chapter 6, page 7 of online textbook

Given the dimensions and resistivity of a wire, determine its resistance. Solution is included after problem.

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

- Complete practice problems on pages 9–10

Find the average drift velocity for ions in a tube of sea water when a voltage is applied across its length. Solution is included after problem.

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

- Complete practice problems on pages 11–2

Determine the resistance of a hollow cylinder between the ends and between the inside and outside. Solution is included after problem.

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

- Complete practice problems on pages 13–4

Discuss the dependence of resistance on dimensions and temperature, and the dependence of power dissipation on resistance.

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

- Complete practice problems on page 14

A conceptual question about current density of a charged sphere spun in a circle.

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

- Complete practice problems on page 14

Given the power and operating voltage of a radiant heater, find the current, resistance and output of the heater.

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

- Complete practice problems on pages 14–5

How long does it take for an individual electron to travel from a car battery to the starter motor?

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

- Complete practice problems on pages 15–6

Describes the concept of a current sheet and explores the calculation of current density per unit length using a Van de Graaff belt example.

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

- Complete practice problems on page 16

How does the resistance of a wire change if it is drawn out so that its length is increased?

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

- Complete practice problems on pages 16–7

Given the power and operating voltage of a lightbulb, find the current, resistance and electricity consumption of the bulb.

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

- Complete practice problems on page 17

Identify how the resistance of a conductor depends on its length and area.

*Physics II: Electricity and Magnetism,*Spring 2007

Prof. John Belcher, Dr. Peter Dourmashkin, Prof. Robert Redwine, Prof. Bruce Knuteson, Prof. Gunther Roland, Prof. Bolek Wyslouch, Dr. Brian Wecht, Prof. Eric Katsavounidis, Prof. Robert Simcoe, Prof. Joseph Formaggio, Andy Neely, Matthew Strafuss, Prof. Eric Hudson, Dr. Sen-Ben Liao

**Course Material Related to This Topic:**

- Complete practice problems on page 1

5-part power problem; finding resistance, power, voltage conditions, and Lorentz force in power lines.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Complete practice problem 1
- Check solution to practice problem 1

5-part problem; determining which bulbs in a circuit are lit when various switches are closed and which are brightest.

8.02

*Electricity and Magnetism,*Spring 2002

Prof. Walter Lewin

**Course Material Related to This Topic:**

- Complete exam problem 1
- Check solution to exam problem 1

Determining relative brightness of light bulbs in a resistor circuit.

8.02X

*Physics II: Electricity and Magnetism with an Experimental Focus,*Spring 2005

Dr. Peter Dourmashkin, Prof. Gunther Roland

**Course Material Related to This Topic:**

- Complete exam problem 1
- Check solution to exam problem 1