Energy is to be transmitted at the rate of 20.0 $\mathrm{kW}$ with only 1.00$\%$ loss over a distance of 18.0 $\mathrm{km}$ at potential difference $\Delta V$ . (a) What is the diameter required for each of the two copper wires in the transmission line? Assume the current density is uniform in the conductors. (b) State how the diameter depends on $\Delta V .$ (c) Evaluate the diameter for $\Delta V=1500 \mathrm{V}$ . (d) If you choose to make the diameter $3.00 \mathrm{mm},$ what potential difference is required?