Errors in basic current balance experiment?

[Ng Sio Hong]

Hi guys, so I'm having a little trouble completing my physics lab report here due to not being able to find many errors to discuss about. The experiment that I conducted makes use of a basic current balance:

http://www.pasco.com/prodCatalog/SF/SF-8607_basic-current-balance/

As you all know, the purpose of this experiment is to test out F=BIL where in this case, my hypothesis was that the force would have a direct proportional increase to the length of the conductor (L). Of course, having plotted a graph shows that it systematic errors and random errors presented itself. The question is, what are these errors and how can i determine the percentage error of the magnetic flux density (B) if i do not have a theoretical value?

 

[Dr. Courtney]

One way to approach measurement error is to make multiple determinations of the output for the "same" input and then average them and compute the standard error of the mean.

Also, suggesting how to assess the error in the current experiment would be easier if we could see your raw data and your efforts to produce a best fit to a line.

A look at your current draft of your lab report would also be helpful.

 

[Dr. Courtney]

I would compute the standard error for each resulting force to give the "error bars" for the graph of force vs. length.

Then I would do a least squares fit (in Excel or other graphing program) of the force vs. length. Does the line go through all the error bars, or are some of the points more than their error bars away from the line?