Question: The RC time constant, also called tau, the time constant (in seconds) of an RC circuit, a irst order RC circuit is composed of one resistor and one capacitor and is the simplest type of RC circuit, and is equal to the product of the circuit resistance (in ohms) and what (in farads)? 
Sentence (from "RC circuit"): Charge transport behaviour in various complex systems, including battery anodes and fuel cells can be described using models of many-element RC networks.
Relevant evidence: No