October 9th

Hi class,

As promised here is your homework for Thursday Oct.15 (no class on wed. due to PSAT testing).

P.434-5 Review Questions #27, 29-33

P.436 Exercises #24, 25, 37, 38, 40

P.437 Problems #7, 8, 10

Some of these questions are about Electric Potential, which we discussed earlier this week, some are on Electric Fields, and some are on Capacitors and Energy Storage.  In some cases, we only briefly mentioned the formulas for calculating Force, Electric Potential (Volts), and Electric Field Strength.  I have given some clarification below, to assist you on those problems.  As always, feel free to use the textbook as a resource.  It is full of helpful examples and definitions.

Electric Fields have both direction (lines of force, vector) and Magnitude.  If a body of Charge q experiences a force F at some point in space, the Electric field E at that point is – E = F/q. The field decreases with distance according to the inverse-square law.

Electric Potential Energy is the Potential Energy an object has due to Work performed on it to overcome the Force due to an Electric Field. Like pushing a positively charged particle against the electric field of a positively charged object (you can think of it like pushing in a spring creates Potential Energy).  Electric Potential is Electric potential per unit charge, and is measured in volts:

Electric Potential = (electric potential energy)/charge

or

1 volt = 1 (joule)/(coulomb)

Both the names Electric Potential and Voltage are common, and can be used interchangeably.

Thanks

Micah