In an experiment that is designed to measure the Earth’s magnetic field using the Hall effect a copper bar 0.500 cm thick is positioned along an east–west direction. If a current of 8.00 A in the conductor results in a Hall voltage of 5.10 x 10-12 V, what is the magnitude of the Earth’s magnetic field? (Assume that n = 8.49 x 1028 electrons/m3 and that the plane of the bar is rotated to be perpendicular to the direction of B.)