In this lab, my partner Ryan and I measured the speed of light. We did so by measuring the delay between a triggered pulse from an LED and the corresponding received pulse generated by a photomultiplier tube (PMT). The procedure we followed is outlined in Professor Gold's manual.
Results
SJK 22:38, 4 October 2009 (EDT)
Our measured speed of light was:
[math]\displaystyle{ 2.9461 \pm 0.0437\times 10^{8} m/s }[/math]
The accepted value is:
[math]\displaystyle{ 2.9979\times 10^{8} m/s }[/math]
For our raw data and to see how we arrived at this value, see the lab notebook.
Conclusions
I was very pleased with this lab. Despite having to compensate for the effect called time-walk, which is a problem encountered when trying to trigger off of signals of differing amplitudes, we managed a reasonable measurement for the speed of light. In fact, our measured value was accurate to the two most significant digits.SJK Steve Koch 22:52, 4 October 2009 (EDT)
In this lab I became familiar with lab equipment such as Time-Amplitude Converters (TACs) and photomultiplier tubes (PMTs). I started to learn how to analyze data at a basic level. I also learned the importance of scrutinizing your data and the procedure you took to determine if there are any major sources or error or if your data is relevant. I still have a bit to learn about data analysis, including more advanced techniques and the significance of the standard error of the mean.SJK 22:43, 4 October 2009 (EDT)
The lab setup was intuitive once we understand what was going on, which actually ended up taking quite some time. Ryan and I thought of several several minor improvements, though I would like to highlight one. We though it would be a good idea to detach the polarizer from the PMT so it can be rotated separately. This change could possibly reduce error.SJK 22:44, 4 October 2009 (EDT)