We also measured the resistivity \(\rho\) of the material, and like the Hall coefficient, we determined it from \(I\) and and a voltage (\(V_L\) instead of \(V_H\)). This too depends on \(n\). The two measurements are related theoretically but also in a practical sense, since some fraction of \(V_L\) tends to show up in our intended measurement of \(V_H\). That is, we end up measuring \(V_H(B) + \eta V_L\) instead of just \(V_H\), and we can separate \(V_{H}\) from \(V_{L}\) since \(V_{L}\) is not field dependent as discussed above.

By plotting, we will theoretically obtain a \(V_{\perp}\) \[\label{eq:MeasuredHallVoltage} V_{\perp} = V_H(B) + \eta V_L\] as a function of \(B\), since \(\eta V_L\) is constant, \[\label{eq:HallSlope} \frac{\Delta V_{\perp}}{\Delta B} = \frac{\Delta V_H}{\Delta B}\] The relationship holds because only \(V_{H}\) is field dependent.