An 18-gauge copper wire (diameter 1.02 mm) carries a current with a current density of (3.30 × 10⁶ , A/m²). The density of free electrons for copper is (8.5 × 10²⁸) electrons per cubic meter. What is the question about?
a. Ohm's Law
b. Magnetic Fields
c. Electric Potential
d. Electrical Conductivity