+ \item \includegraphics[width=14cm]{hall.eps}
+ \item \[
+ \frac{dp}{dt}=-e\left(E+\frac{p}{m}\times B\right)-\frac{p}{\tau}
+ \]
+ steady state ($\frac{dp}{dt}=0$):
+ \begin{itemize}
+ \item $x$ component: $0=-eE_x-\frac{eB}{m}p_y-\frac{p_x}{\tau}$
+ \item $y$ component: $0=-eE_y-\frac{eB}{m}p_x-\frac{p_y}{\tau}$
+ \end{itemize}
+ setting $j_y$ to zero in the second equation ($\Rightarrow p_y=0$):
+ \[
+ E_y=-\left(\frac{B}{m}\right)p_x
+ \stackrel{j=-ne\frac{p}{m}}{=}-\left(\frac{B}{ne}\right)j_x
+ \]
+ \[
+ \Rightarrow R_H=-\frac{1}{ne}
+ \]
+ \item \begin{itemize}
+ \item electron density: $n=\frac{V\rho}{A_ru}/V=\frac{\rho}{A_ru}$
+ \item $R_H=-\frac{1}{ne}=-\frac{A_ru}{e\rho}$
+ \item $j_x=\frac{I}{ld}$
+ \item $E_{Hall}=E_y=R_HBj_x=\ldots=5.3 \cdot 10^{-5} \, \frac{V}{m}$
+ \item $U_{Hall}=E_y l=\ldots=-7.95 \, \mu V$
+ \end{itemize}