Physics307L:People/Mondragon

This is my page for Junior Lab, Fall 2007. Links to my notebook and my main OWW page, where you can find contact info, below

My 307L lab notebook

My 307L lab notebook Quick link to lab manual here

My main OWW user page

User:Tomas A. Mondragon

Oscilloscope Lab Summary

Main notebook entry here.

see comment

Steven J. Koch 23:59, 2 October 2007 (EDT):Good work during this lab, Tomas. I think you've calculated the random uncertainty correctly (based on your email comments. So, the remaining question is: why is the accepted value so far outside of your uncertainty range??? This will be a puzzle for future experimenters in the 307L lab.

To get practice in using an oscilloscope, I adjusted the volts/div, time/div, and trigger settings on the oscilloscope to get the oscilloscope to display a ~200Hz sine wave, triangle wave, and square wave. Adjusting the time and voltage settings improved how well the wave form were displayed on screen, and adjusting the trigger appropriately made the waveform displayed on the screen steady.

To gain experience taking measurements with an oscilloscope, I measured the amplitudes of these waveforms using the grid on the scope's display, the scope's horizontal cursors, and the scope's peak-to-peak measurement function. I then used the scope's vertical cursors to measure the scope's characteristic AC coupling fall time. The voltage the oscilloscope measured under AC coupling after a DC voltage step up declined to 10% after about 32ms meaning the characteristic fall time was about 14ms

e/m ratio summary

This experiment worked better than I initially expected. I haven't done any proper number crunching yet, but the e/m ratio that Lorenzo and I measured seems to float around [math]\displaystyle{ 2.9\pm0.2\times 10^{11} \tfrac{\mbox{coulombs}}{\mbox{kilogram}} }[/math]

Further investigation can be done in how electrons lose energy to the helium in the bulb and how this effects radius.