A "dark" type of this phenomenon manifests in light-sensitive devices like 
A "dark" type of this phenomenon manifests in light-sensitive devices like CCDs even when there is no light entering the device. A rectifier is used to force this phenomenon to be unidirectional. The areal density of this quantity equals conductivity times electric field. When these phenomena are "steady", the magnetostatic approximation holds, whence the magnetic field generated by them is described by the Biot-Savart law. Inductors resist changes in this quantity. Per Ohm's law, this is the ratio of voltage to resistance. For 10 points, name this quantity which measures the flow of electric charge in units of amperes.
A "dark" type of this phenomenon manifests in light-sensitive devices like CCDs even when there is no light entering the device.
electric current 