Physics307L F09:People/Mondragon/Notebook/070919

Excel File

Here is the Excel File that Lorenzo uploaded.

Mass of the Electron(second week)

##this script is here to document the steps I took in processing data from the e/m ratio experiment. Hoorah.

#octave
#runs best in octave, then matlab

varyAleft=[200,200,200,200    #ring radius on the left, varying current
1,1.2,1.4,1.6                 #first row is voltage, second is current
4.9,4.8,4.6,4.5               #third is radius, and fourt is error on radius
0.2,0.2,0.3,0.3]              #units are volts, amperes, centimeters, cm

varyAright=[200,200,200,200    #ring radius on the right, varying current
1,1.2,1.4,1.6 
4.3,3.7,3.2,3.1
0.1,0.2,0.1,0.2]

varyVright=[200,220,240,260    #ring radius on the right, varying voltage
1,1,1,1 
4.3,4.5,4.7,4.8
0.2,0.1,0.2,0.1]

varyVleft=[200,220,240,260    #ring radius on the left, varying voltage
1,1,1,1 
4.8,4.9,5.1,5.2
0.2,0.1,0.2,0.3]

#the voltage and current uncertainties were constant, so, just assign constants for their error
Verror=1
Aerror=0.01

#Clump all the data in one variable for convienence purposes
rawData=[varyAleft varyAright varyVleft varyVright]

#compute the bfield strength according to the current
Bmagnitude=7.8e-4*rawData(2,:)
BmagnitudeError=Aerror*7.8e-4      #propagate error via chain rule

#e/m ratio computation. e/m= 2*voltage/(Bfield^2*radius(in meters)^2)
e_mRatio=2*rawData(1,:)./(Bmagnitude.^2.*(rawData(3,:)*10^(-2)).^2)

e_mError=2*Verror./(Bmagnitude.^2.*(rawData(3,:)*10^(-2)).^2+4*BmagnitudeError*rawData(1,:)./(Bmagnitude.^3.*(rawData(3,:)*10^(-2)).^2)+4*rawData(1,:).*rawData(4,:)*10^(-2)./(Bmagnitude.^2.*(rawData(3,:)*10^(-2)).^3)

--Tomas A. Mondragon 14:45, 10 October 2007 (CDT)