Notes:

Drift_Vel.pngcurrentresist.png

One formula I left off was P = I2R

Reswire.png
Resistance as a result of temperature change: So If you are looking a current change as a result of temperature change, you will look at the current at the hot temperature x the resistance at the hot temp = the current at the cold temperature x the resistance at the cold temperature. To find the resistance at a temperature use this following information. The T0 is usually 20 oC.
The p for copper is 1.7 x 10-8 ohm meters.


rescoeff.png

Video:


Labs:

Lab 1


Lab 2


Lab 3


Lab 4


Battery-Resistor Circuit
Click to Run

Discussion:

re: 19 Current & Resistance

andreashaycumberland Jan 27, 2010 7:20 am
The work is kind of simple. Just manipulating formulas really.
I found http://www.jampro.com/index.php?page=the-ohms-s-law-formula-wheel which gives you pretty much all the formulas you need except stuff that conttains joules in the problem which I couldn’t find in the book but you can just look up online.
the labs for partner 1 were pretty straight forward. just make sure you have all the different junctions connected correctly or the power won't flow through the bulbs at all.
shay

nchshadenj Feb 2, 2010 9:42 am
The majority of problems in the current packet are fairly simple. You just have to be able to plug things into and manipulate the formulas. Some of the main formulas are I=Q/t and R=V/I. Know that Q=energy in the forms of C and J. The two different currents are A(C/s) and W(J/s). Make sure that all your units are correct or your numbers will be wrong.
Good luck,
Haden J.

nchshadenj Feb 5, 2010 7:12 am
The lab for partner two in this section is easy and fun. Just follow the instructions given to you, and simply answer the questions based on your observations. If you have any extra time, you may want to go back and play with the circuits, light bulbs, and switches. It’s pretty fun and will allow you to learn a little more on how electricity actually works in your home.
-Haden J.

ethanp1 Apr 12, 2010 7:07 am
This chapter is fairly easy just manipulating minor formulas. Remember Watts are J/s and when finding price per kilowatt*hour to use this to convert and that a kilowatt*hour is 3.60e6J

nchsclarkm Apr 14, 2010 7:16 am
Attention lucky student: This is the easiest chapter you will do.
Current and Resistance was actually kind of fun. It's a great relief as opposed to the other difficult units you may have already done. The problems are repetitive and consist mainly of just finding out what you are giving and using the correct formula.
The three main formulas are P(Watts)=I(Amps)V, R(Resistance)=V/I(A), and I(A)=Q/t(time in seconds).
For the cost problems, remember that a kWh = 3.6e6J. Just get the watt value to kW, multiply by the amount of hours, and multiply that value by the fee the company charges.
The lab was fun and entertaining. It was a PhET activity that involved constructing a circuit and recording the observations. They’re lots of questions or anything either and it’s amusing to make your own unique circuits and try different things.
Have fun :)
Michael Clark