## Tuesday, February 16, 2016

### Classes today

Periods 1-2, 8-9:

Check out videos on Biot-Savart today. In the Production of Magnetic Fields packet from last time, there is a page for Biot-Savart - this is like the Non-Gauss cases for electric fields, where we need to figure out what one moving charge does for its magnetic field, and then sum them up (i.e. integrate).

The first video is for the magnetic fields of point charges. Take good notes on this. The second video is magnetic fields for straight wires with ends.  There is a third video on the magnetic field due to a loop of current (like the Helmholtz coil in the CRT lab last time). Take good notes on these.

This is a lot of information, and we'll process it more tomorrow. Keep track of any questions you come up with. After the videos, take a look at the magnetism quizzam from last time. Solutions are on the website, in the magnetism folder. Start an error analysis on this.

For homework, try Ch 27 #41; Ch. 28 #8

Periods 3-4:

We will take a look at the analysis of resistor circuits. Watch a video on this for series and parallel resistor circuits. This is going to come from results of the labs last week.

Total resistance in series = R1 + R2 + R3 + ...       just add them up
Total resistance in parallel = [ 1/R1  + 1/R2  + 1/R3 ]^(-1)    add up reciprocals of each branch, then flip over the answer

Take notes on all this from the video. There are some examples on page 4 of the packet. See if you can do anything with problems 1 and 2 on page 5. The remaining time in class can be spent completing the two labs from last week. Keep track of all questions that come up for tomorrow.