| Code Number : | 7B30.23 |
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Reprinted by permission of Dick Berg, University of Maryland, for use on this website. The demonstrations contained and referenced herein are listed for the purposes of cataloging and describing physics demonstrations which should be conducted only under the direction of a trained instructional support professional or physicist. These demonstrations are not presented for the purpose of being conducted by persons unconnected to this Facility and/or persons not consulting with or being supervised by the recognized instructional support professional or physicist and his/her staff. The University is responsible only for those demonstrations carried out using its own equipment using established safety and scheduling policies, and bears no responsibility for those choosing to use this source material for their own purposes. All demonstrations described and contained herein are public domain, and can also be found in reference materials in libraries, bookstores, and electronic sources. Further information regarding legal liability in use of demonstrations and labs will be found on the web site Injuries in School/College Laboratories in USA. The University of Iowa Disclaimers: University of Iowa Disclaimer All Rights Reserved.. |
| Condition : | Excellent |
| Principle : | Critical Potential in a Gas |
| Area of Study : | Modern Physics |
| Equipment : | Franck
- Hertz Xenon Tube Unit, 0 to 20 VDC Power Supply, 2 - Variacs, 2 -
6 volt Transformers, Volt and Amp Meters, Oscilloscope. |
| Procedure : | By carefully varying the voltage on the 0 - 150 VDC power supply three different peaks corresponding to three different energies of helium may be shown at one time. It will take several minutes for the dry cell to stabilize to an amperage output of about .1 to .2 amps. The amperage may be as high as 4 to 5 amps when the dry cell is first connected. An amp meter should be used to monitor this condition. NOTE: MAKE SURE ALL THE POWER SUPPLIES ARE AT MINIMUM OUTPUT BEFORE THEY ARE HOOKED TO THE TUBE AND TURNED ON. THIS WILL INSURE THAT THE TUBE REMAINS UNDAMAGED!! Note that the oscilloscope hookup that works best for our situation is a little different than the diagram that comes with the tube instruction. |
