A Whirlwind Tour of Physics
Assignment 5

Jim Mahoney (mahoney@marlboro.edu)

What :
Electricity and Magnetism. Electric Fields. Voltage, Current, Resistance. Maxwell's Equations. Simple Circuits. Magnetism: cause (current), effect (on moving charge). Induction.

Readings :

• Seven Ideas : chapter 6, pgs 144-155
• Great Ideas : pgs 113 - 118
• Conceptual Physics chapters 21, 22, 23, 24, 25 (lot of material)
• Shamos, Great Experiments in Physics : chapter 9, Oersted

Lab:

(1) Your last lab before your project is on electricity and magnetism. Examine or test some magnetic or electrical phenomena. You can set up a simple circuit, measure voltage, current, and resistance, build and electromagnet, test methods of "shielding" your radio, or other ideas suggested in the electricity section of Flying Circus, in class, or from Conceptual Physics. As always, talk to me for ideas.

(2) It's time to propose a project. Run some ideas for a final project by me. You need to start working on a multi-week, major-paper-sized-project lab of your choice, on any topic we have covered in the first half of the course. Let me know, in writing, what you're planning.

Discussion:

1. What is the "Electric Field" and the "Magnetic Field"? How can you measure their presence? How can you create them? Be as specific as you can.
2. Explain what a "volt" is. How is it related to force and/or energy?
3. A hydro-electric power station uses a water-fall (or other water pressure) to spin a turbine which generates electricity. This electricity runs through power lines to your house where it runs your toaster and burns your toast. How does the generator work? In other words, how is the energy of moving water transformed into electrical energy? Discuss the different forms the energy takes as it travels from the waterfall to your toast.
4. What is light, and how is it related to electric and magnetic fields? What is the difference between red light and green light? Are there other forms "light" can take?
5. Sketch a simple electrical circuit which includes a battery, some wires, and a resistor. Explain what the "current" is, what causes it, and how you can measure it.
6. Explain the difference between "AC" and "DC" current. Which comes out of the plug in your room? Why?
7. It has been said that all chemistry, life, and everyday phenomena are essentially manifestations of electrical physics. Do you agree? Explain why or why not.