2015 BFY II Abstract Detail Page
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||Electron’s Charge-to-Mass Ratio Experiment: Students Laser-Focused on Perfection.
||The charge-to-mass ratio of an electron was measured using J.J. Thomson's method (1987). An electron gun generated and accelerated a beam of electrons inside a helium filled vacuum tube. The tube was surrounded by a Helmholtz coil that produced a magnetic field curving the electron beam into a circular path. By measuring the current through the Helmholtz coil, voltage across the electron gun and diameter of electron path, the charge-to-mas ratio of the electron was calculated. By using various methods to measure the diameter of the path (visual versus laser), values were found between 7% and 0.8% of the accepted value.
Influence of several additional factors on final result was determined: values of accelerating voltage, values of coil's current, and precision limits in visual measurement.
Necessity of additional mounting system for the lasers which would expedite the alignment process is discussed. Additionally, it is concluded that more measurements under varying conditions are necessary to determine the most accurate settings for voltage and current
Dr. Elena Gregg
Oral Roberts University
7777 S Lewis Ave
Oral Roberts University, Engineering Department, undergraduate Engineering Physics students:
Wesley Odom, Leif Peterson, Joshua Williams
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