What is the current in a steel conductor 12m long and 4mm2 cross-section, to which a voltage of 72mV is applied?

What is the current in a steel conductor 12m long and 4mm2 cross-section, to which a voltage of 72mV is applied? (steel resistivity 0.12 Ohm • mm2 / m)

The electrical resistance R of a steel conductor with a length of L = 12 m with a cross section of S = 4 mm ^ 2 is determined by the formula R = (ρ ∙ L): S, where ρ = 0.12 Ohm ∙ mm ^ 2 / m is the resistivity of steel. To determine what is the current strength I in this steel conductor, to which the voltage U = 72 mV = 0.072 V is applied, we use Ohm’s law for a section of the circuit:
I = U: R or I = U: ((ρ ∙ L): S), we get,
I = U ∙ S: (ρ ∙ L).
Substitute the values of physical quantities in the calculation formula:
I = 0.072 V ∙ 4 mm ^ 2: (0.12 Ohm ∙ mm ^ 2 / m ∙ 12 m);
I = 0.2 A.
Answer: the current in the steel conductor was 0.2 A.