Ohm's Law states that this quantity is equal to voltage divided by current.
One manifestation of this phenomenon is the energy difference between the HOMO and LUMO states in a molecule, and is called the band gap, while its dependence on temperature is described by Matthiessen's Rule. Materials that have a value of zero for this quantity are subject to the Meissner effect, and are called (*) superconductors. In circuits, this quantity is additive for two of its namesake objects in series. Ohm's Law states that this quantity is equal to voltage divided by current. For 10 points, name this measurement of an opposition to current flow in a material.
One manifestation of this phenomenon is the energy difference between the HOMO and LUMO states in a molecule, and is called the band gap, while its dependence on temperature is described by Matthiessen's Rule.
electrical {resistance}