Electrical conductance of solution

According to Ohm's law, the electrical resistance $R$ of a conductor equals the electric potential difference $V$ divided by the electric current $I$:

The SI unit of potential is volt (V) and that of current is ampere (A). The unit of electrical resistance is ohm, denoted by the symbol $\Omega$ (omega); thus $\Omega = \mathrm{V\,A^{-1}}$.

The electrical conductance $G$ of a solution is the reciprocal of its resistance:

The SI unit of $G$ is siemens, denoted by S, which is equal to $\Omega^{-1}$. Therefore we can write $\mathrm{S = \Omega^{-1} = A\,V^{-1} = C\,V^{-1}\,s^{-1}}$, where C represents coulomb, the unit of quantity of electricity, related to current strength in ampere and time in seconds as $\mathrm{C = A\,s}$.

The electrical resistance of a conductor is proportional to its length $l$ and inversely proportional to its cross-sectional area $a$: …