Jessica Alba

Calculating error in Physics lab report?

I’m handing this report in a few hours and there’s a little detail I want to sort out. We did the Franck-Hertz experiment about atom excitement, and gathered data of accelerating voltage and anodic current. Then I put the data in a diagram, which naturally shows curves that go up and then down (kind of like sinusoid, but it’s not a sine function). The diagram was current with respect to voltage. We were asked to find the distances between the local minima (in volts) and then their mean and error.

The error on our experimental voltmeter was +/- 0.1 V. I can easily find the mean, but I’m not confident about it’s error… So should I use this error of the voltmeter (which makes sense, since the mean is 5 Volts and the energy of the first excited state of Hg -which is what we want to find- is 4.9 eV) or should I use some kind of error propagation (which in turn doesn’t make sense, since I don’t have any function but a mean).

Thank you!