Ohms Law. If a potential (E) volts is applied across a resistance (R) ohms, the resulting current is (I) amps the relationship between (E), (I) and (R) is given by Ohm’s law, i.e..That the current flowing though a conductor is directly proportional to the voltage applied across the conductor and inversely proportional to the resistance of the conductor. Thus, the current flowing through the resistance is directly proportional to the reciprocal of the resistance and is called the conductance, which is measured, in reciprocal ohms or ‘mho’s’. The resistance of a conductor varies directly as its length (l), inversely as it’s cross sectional area (A), . Where (ρ) is the specific resistance or resistivity of the conductor, which is the resistance in ohms of the specimen 1 cm in length and 1 sq. cm in cross section.

Further Information on this Topic can be found in the books of R.P.W. Scott by following the listed links