This quantity is zero for an ideal ammeter, and it is the inverse of conductance.
The mean square Johnson-Nyquist voltage noise is proportional to the square root of Boltzmann's constant times temperature times this quantity. At the boundaries of materials with a low value of this quantity, Andreev reflection will occur, and those materials will have little to no internal magnetic field. Compounds of cadmium and group 16 nonmetals like sulfur or selenium generally exhibit a decrease in this quantity when they absorb photons and are thus used in (*) photocells. For a wire, this quantity equals rho times length divided by its cross-sectional area. This quantity is zero for an ideal ammeter, and it is the inverse of conductance. The generalization of this quantity to AC circuits is denoted Z and called impedance. For 10 points, identify this quantity which, according to Ohm's Law, is equal to voltage divided by current.
The mean square Johnson-Nyquist voltage noise is proportional to the square root of Boltzmann's constant times temperature times this quantity.
electrical resistance