2. Suppose a long, straight, copper wire with a circular cross-sectional area of 2.1 mm² carries €0.) (d) If a current of 16 A. The resistivity of the material is 2.0 x 10-8 m. (a) What is the uniform electric field in the material? (b) If the current is changing at the rate of 4000 A/s, at what rate is the electric field in the material changes? (c) What is the displacement current density in the material in part (b)? (Hint: Since K for copper is very close to 1, use € = the current is changing as in part (b), what is the magnitude of the magnetic field 6.0 cm from the center of the wire? Note that both the conduction current and the displacement current should be included in the calculation of B. Is the contribution from the displacement current significant?