MATLAB code document

%% Constant V Vconst=360; I=[1.22 1.27 1.32 1.37 1.42 1.47 1.52 1.57 1.62 1.72];

% radii in meters VR1=[3.4 5.2 3.8 5.2]*10^-2; VR2=[3.5 5.2 3.5 5.3]*10^-2; VR3=[3.4 5.1 3.6 5.0]*10^-2; VR4=[3.4 5.0 3.4 4.8]*10^-2; VR5=[3.0 4.7 3.3 4.7]*10^-2; VR6=[3.2 4.8 3.5 4.5]*10^-2; VR7=[2.9 4.5 3.5 4.4]*10^-2; VR8=[3.0 4.3 3.3 4.4]*10^-2; VR9=[2.9 3.9 3.0 4.0]*10^-2; VR10=[2.4 3.5 3.0 3.7]*10^-2; % average radii VRavg=zeros(1,10) for k=1:10 stringy=sprintf('mean(VR%d)',k) VRavg(k)=eval(stringy) end

% radii errors VRerrors=zeros(1,10); for k=1:10 stringy=sprintf('sqrt((sum((VR%d-mean(VR%d)).^2))/3)',k,k) VRerrors(k)=eval(stringy) end VRerror=mean(VRerrors)

%least squares fit: VRawfit=polyfit(I,VRavg,1); VRawval=polyval(VRawfit,I);

%plots figure(1) hold on plot(I,VRawval,'k') errorbar(I,VRavg,VRerrors,'*'); xlabel(' I, (Amps)');ylabel('Radius (m)'); title('R vs. I at V=360V') hold off saveas(figure(1),'ConstantV_rawdata.jpg')

%e/m ratio from slope Vleft=((7.8E-4)*(VRavg)).^2/(2*Vconst); Vright=I.^-2; Verrs=((7.8E-4)*(VRerrors)).^2/(Vconst); Verr=((7.8E-4)*(VRerror))^2/(Vconst); Vfit=polyfit(Vright,Vleft,1); Vval=polyval(Vfit,Vright); figure(2) hold on plot(Vright,Vval) errorbar(Vright,Vleft,Verrs,'r*'); xlabel(' I^-2, (Amps^-2)');ylabel('(7.8E-4*R)^2/2V (T*m^2/A*V)'); title('m/e slope at V=360V') hold off saveas(figure(2),'ConstantV.jpg')

Veoverm=Vfit(1)^-1 Veovermerr=Veoverm/1.756E11-1

%% Constant I Iconst=1.35; V=[441.2 430.5 420.5 409 399.9 390.1 380.0 369.8 360.0 350.0];

% radii in meters IR1=[4.0 6.0 4.0 5.5]*10^-2; IR2=[4.0 5.5 4.0 4.5]*10^-2; IR3=[3.9 5.4 3.9 5.3]*10^-2; IR4=[3.9 5.3 3.8 5.3]*10^-2; IR5=[3.8 5.2 3.8 5.1]*10^-2; IR6=[3.7 5.1 3.7 5.0]*10^-2; IR7=[3.5 5.0 3.6 4.8]*10^-2; IR8=[3.4 4.9 3.5 4.8]*10^-2; IR9=[3.3 4.8 3.5 4.8]*10^-2; IR10=[3.3 4.8 3.4 4.5]*10^-2; % average radii IRavg=zeros(1,10) for k=1:10 stringy=sprintf('mean(IR%d)',k) IRavg(k)=eval(stringy) end

% radii errors IRerrors=zeros(1,10); for k=1:10 stringy=sprintf('sqrt((sum((IR%d-mean(IR%d)).^2))/3)',k,k) IRerrors(k)=eval(stringy) end IRerror=mean(IRerrors)

%least squares fit: IRawfit=polyfit(V,IRavg,1); IRawval=polyval(IRawfit,V);

%plots figure(3) hold on plot(V,IRawval,'k') errorbar(V,IRavg,IRerrors,'*'); xlabel(' V, (V)');ylabel('Radius (m)'); title('R vs. V at I=1.35A') hold off saveas(figure(3),'ConstantI_rawdata.jpg')

%e/m ratio from slope Ileft=((1.053E-3)*(IRavg)).^2/2; Iright=V; Ierrs=((1.053E-3)*(IRerrors)).^2; Ierr=((1.053E-3)*(IRerror))^2; Ifit=polyfit(Iright,Ileft,1); Ival=polyval(Ifit,Iright); figure(4) hold on plot(Iright,Ival) errorbar(Iright,Ileft,Ierrs,'r*'); xlabel(' V, (V)');ylabel('(1.053E-3*R)^2 (T*m^2)'); title('m/e slope at I=1.35A') hold off saveas(figure(4),'ConstantI.jpg')

Ieoverm=Ifit(1)^-1 Ieovermerr=Ieoverm/1.756E11-1

%FINAL RESULT eoverm=(Veoverm+Ieoverm)/2 VIeovermerr=eoverm/1.756E11-1