What is the cross-sectional area of a copper wire with a current strength of 0.05A at a voltage of 5V?

What is the cross-sectional area of a copper wire with a current strength of 0.05A at a voltage of 5V? wire length 400m.

According to Ohm’s Law:
I = U / R, I – current strength (I = 0.05 A), U – voltage (U = 5 V), R – copper wire resistance (Ohm).
R = ρ * l / S, ρ is the resistivity of the copper wire (ρ = 0.018 Ohm * mm ^ 2 / m), l is the length of the copper wire (l = 400 m), S is the cross-sectional area of the copper wire (mm ^ 2 ).
Let’s calculate the cross-sectional area of the copper wire:
I = U / R = U * S / (ρ * l);
S = I * ρ * l / U = 0.05 * 0.018 * 400/5 = 0.072 mm ^ 2.
Answer: The cross-sectional area of the copper wire is 0.072 mm ^ 2.