First discovered in 1879 at Johns Hopkins, this effect can be used to  dete
First discovered in 1879 at Johns Hopkins, this effect can be used to  determine the density of charge carriers in a conductor, as well as their  sign. It is created when a magnetic field is applied perpendicular to a  current-carrying conductor, and creates a potential difference across the two  sides of the conductor. For ten points, what is this effect that is vital to  the study of semiconductors?
First discovered in 1879 at Johns Hopkins, this effect can be used to  determine the density of charge carriers in a conductor, as well as their  sign.
the Hall effect