A flat, rectangular slab of conducting material has length \(L\), width \(w\), and thickness \(t\). A uniform magnetic field of magnitude \(B\) is directed perpendicular to the top face of the slab. A constant current \(I\) flows along the length \(L\) of the slab, carried by charge carriers each having charge magnitude \(q\) and volume number density \(n\). Which of the following expressions represents the magnitude of the Hall voltage \(V_H\) established across the width \(w\) of the slab?