PHYSICS 182 Lecture Notes - Lecture 30: Magnetic Moment, Electric Dipole Moment, Ferromagnetism

A magnetic field can be used to determine the sign of chargecarriers in a current-carrying wire. Consider a wide conductingstrip in a magnetic field oriented as shown in fig. 19.34
The charge carries are deflected by the magnetic force andaccumulate on one side of the strip, giving rise to a measurablevoltage across it. (this phenomenon is known as the Hall effect) Ifthe sign of the charge carriers is unknown (they are eitherpositive charges moving in the opposite direction), how doespolarity or sign of the measure voltage allow the sign of thecharge to be determined? Assume that only one type of chargecarrier is responsible for the current.