- #1

Taylor_1989

- 402

- 14

## Homework Statement

I am having a issue with calulating my errors for this particular experiment the reason I will detail below. I have also print sceend in the section of my lab report to show the experimental setup etc.

Lab Script

So in the lab during the experiment the tesla meter could neve be zero and this was due to interferce, so the readings would go from 0.00mt to 0.03mt so we took an average, and this was the same for all the readings. This is shown more clearly in my table of results:

So of the averages have been rounded or auto corrected by excel which I will need to adjust.

So my throughts are this is a random error and not a systematic as I can't reproduce the same results each time, we did take a repeat of the first couple of values a did get differnt readings for the average. So is it possible to use a SD to calulate the error on this, or is this inccorect? I would then plot this as the Y error bars

My second issue is what they mean but "

**Compare with theoretical estimates"**. Dose this mean just take the equation:

$$B=\frac{\mu_{0} I}{2R} [1]$$

And sub in the current 0, 2,...16 with the assumtion there is no error on the equipment, or dose it mean with the error on the equipment if so, I would have to propagte the errors, which would be anouther set of Y axis error bars. But as we have been told to plot on the same axis the error bars would overlap, so I can't see this being correct.

Here is my graph without any error bars at the moment:

I am also having the same issue with the second part of the experiment, where we keep the amp the same at 16A and move the detector along the x-axis in the postive direction by 10cm and the negitive direction by 10cm. Beacuse now in my mind I have an uncerity on the ruler and the fluxuation in the magnetic field. So how can I plott the error bars for this type.

One of my ideas was to do the following.

Calulate the SD on the magnetic field then use the equation:

$$B=\frac{\mu I R^2}{2(R^2+x^2)^{3/2}} [2]$$

and then use propagation with the uncerity on the ruler as ##0.5cm## and combine the two, but then thinking a little more I don't think this would work.

The equation we are told to use for our error calulations is the

$$(\delta f)^2=\left(\frac{\partial \:f}{\partial \:x}\left(\delta \:x\right)\right)^2+\left(\frac{\partial \:f}{\partial \:y}\left(\delta \:y\right)\right)^2 [3]$$

where delta x and y are my estimated uncerity, i.e my ruler being 0.5cm beacuse i did not repeat the give measument.

Just to clarify, we had a very quick and very brife course in stats so much so, that my knowledge is very limited and I am trying to learn as I go.