Physics307L F09:People/Joseph/Lab2

Summary
The point of this lab was to determine the e/m ratio of the electron. e being the charge of the electron, and m being the mass. The procedure and data collection can be found in my notebook.

The best guess we have at the actually $$e/m$$ ratio for electrons would be: 3.13 x 10^11 C/kg. This value was the least off from the accepted value (78%) even though I could not say what we did differently when collecting this data from the other. Our overall range of data was anywhere from 78% to 130% off. Now this is a large discrepancy, it is surprisingly consistent. This implies some systematic error, which I discuss in the data analysis portion of the lab report.

If I had the time to redo the lab I'd do a couple of things differently: 
 * I'd take a ton more data. We had a total of 16 useful data points.  I'd like to have over a hundred.  As discussed in class, the central limit theorem illustrates how this would help us get some consistent, usable data.
 * I'd like to isolate this experiment a bit more. Move it to a location away from any interfering light sources, or possible magnetic influences.  Set up the power sources a good distance away and isolate the apparatus as much as possible.
 * I'd like to know what the electron gun is made up of. This would help us determine a work function that we could account for and reduce our error by truly understanding what phenomena we are manipulating, and what phenomena is just something to deal with.

Overall, this is a great lab. Its difficult and inaccurate, but teaches you a lot about questioning your data and procedure. Its better for learning the actual process of taking good data, than for getting the true answer. This is the kind of lab where you make your mistakes so you don't make them so easily in the future.