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Unformatted text preview: Electron Charge to Mass Ratio Nathan Quinn 2262008 Abstract The experimental goal was to determine the chargetomass ratio of an electron. The experiment involved using an electric field to accelerate the speed of an electron, followed by using a magnetic field developed by Helmholtz coils to change its path in a controlled manner so as to determine the current required to generate such a magnetic field. This was done twice at two different voltages (a total of four times), switching the direction of current between runs to help account for the magnetic field of the earth. The result obtained, which was an average of the runs, was 1.74 * 10 11 C/kg, which was approximately 1.0% in error of the accepted value. The charge to mass ratio of an electron can, therefore, be assumed to be constant. 1  Purpose and Theory The purpose of this experiment is to understand the force a charged particle withstands while in a magnetic field through the analysis of the electron’s charge to mass ratio. The theory behind this is based on equations that relate the mass, velocity, and charge of the particle to the current and precise model used to generate the magnetic field: Force of a Magnetic Field ( 29 B v e F B v v v × = Eq. 1 Force on an Electron due to a Centripetal Force r r mv F ˆ 2 = Eq. 2 Charge to Mass Ratio of an Electron 2 2 2 r B V m e = Eq. 3 Magnetic Field from Electrical Current I R N B = 125 8 μ Eq. 4 For the above equations: e = charge of an electron (C) m = mass of an electron (kg) V = voltage used to produce electrons (V) B = strength of magnetic field (T) r = radius of the path traveled by the electron (m) N = # of Helmholtz coils R = radius of Helmholtz coils (m)...
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 Spring '08
 Everett
 Electron, Charge, Mass, Magnetic Field, Electric charge, 1.0%, 1.13%, 0.33m

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