| If an electric current, Ix, passes along a sheet of conducting material and a magnetic field, Bz, is placed normal to the current, an electric field is produced perpendicular to both Bz and Ix. This is an application of the Lorentz force.
The effect is named after Edwin H Hall who discovered the effect in 1879 while he was a graduate student at Johns Hopkins University, Baltimore. He attached a wire to either side of a piece of gold foil and investigated the results when he passed an electric current across it.
The electric field is measured as a voltage called the Hall voltage. For an given material, the Hall voltage is proportional to the current and magnetic field used to obtain it. Different materials have different Hall voltages thus an application of the Hall effect is measurement of unknown magnetic fields and currents. | 
