User:Michael R Phillips/Notebook/Physics 307L/2008/11/26: Difference between revisions
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For this lab, we will be measuring a value for Planck's constant (<i>h</i>) by relating it to photoelectric effects caused by a Mercury lamp's light incident upon a cathode. There a few safety concerns that we will need to be careful about. These are high voltage, hot Mercury tube, and risk of breaking the tube. All of these hazards have already been dealt with in previous labs (see [[User:Michael R Phillips/Notebook/Physics 307L/2008/10/29 | Balmer Series]]) so we were already prepared for them. | For this lab, we will be measuring a value for Planck's constant (<i>h</i>) by relating it to photoelectric effects caused by a Mercury lamp's light incident upon a cathode. There a few safety concerns that we will need to be careful about. These are high voltage, hot Mercury tube, and risk of breaking the tube. All of these hazards have already been dealt with in previous labs (see [[User:Michael R Phillips/Notebook/Physics 307L/2008/10/29 | Balmer Series]]) so we were already prepared for them. | ||
=== | ===Setup=== | ||
The lab was setup already, but we will still supply a brief description. We have a Mercury light source outfitted with a converging lens and diffraction grating pointed towards a "h/e" apparatus. This h/e apparatus is just a small circuit contained in a box. This circuit is basically just a piece of metal (the "cathode") which will receive photons from the Mercury lamp connected in series to a battery and an output (and ground). The battery is there so that we will have a voltage source that we can vary to measure the stopping potential from the output. The ground just resets the circuit so that the potential is zero again just before the cathode. | |||
Revision as of 14:33, 26 November 2008
 Planck's Constant Lab
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Planck's Constant (Photoelectric Effect)Introduction & SafetyFor this lab, we will be measuring a value for Planck's constant (h) by relating it to photoelectric effects caused by a Mercury lamp's light incident upon a cathode. There a few safety concerns that we will need to be careful about. These are high voltage, hot Mercury tube, and risk of breaking the tube. All of these hazards have already been dealt with in previous labs (see Balmer Series) so we were already prepared for them. SetupThe lab was setup already, but we will still supply a brief description. We have a Mercury light source outfitted with a converging lens and diffraction grating pointed towards a "h/e" apparatus. This h/e apparatus is just a small circuit contained in a box. This circuit is basically just a piece of metal (the "cathode") which will receive photons from the Mercury lamp connected in series to a battery and an output (and ground). The battery is there so that we will have a voltage source that we can vary to measure the stopping potential from the output. The ground just resets the circuit so that the potential is zero again just before the cathode.
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