Here are notes that I needed to write down for some of the Lab Sessions. I was closer to a PC than my log book at the time, so I wrote them on my web page!
I have decided to force the line through the origin because the error in the y-intercept value (0.0649) is considerably larger than the y-intercept itself (0.0099). This comparison is the standard statistical method of deciding if a line should be forced through the origin, as per Lab Session 2A.
The final gradient (R/L), as found by Excel: 0.219 ± 0.0012.
The radius of the copper wire, as calculated in Lab Session 2A: see above
R = p l/(πr2)
R/L × (πr2) = p
...where R/L is the gradient. This gives
p = 1.72 × 10 -5