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a) A rectangular metal strip of length $L$, width $w$, and thickness $t$ sits in a uniform magnetic field $B$ perpendicular to the strip and into the page as shown. The material has resistivity $\rho$ and a free (conducting) electron (charge $q = -e$) density of $n$. A voltage $V_0$ is connected across the strip so that the electrons travel from left to right as shown.

find an expression for the Hall potential (the potential difference across the strip from top to bottom) in terms of the given quantities. Note (as a set of recipe/hints) that you'll have to start by relating $I$ (the current in the strip) to the givens, and then translate that into a form involving the drift velocity $v_d$. From $v_d$ and your knowledge of magnetic forces you should be able to determine the electric field and then the potential across the strip in the steady state.