27. Resistors & DC Circuits

What is the current density in a wire with a radius of $0.815\mathrm{mm}$ carrying a current of $5.0\mathrm{A}$?

Typical household wiring in the United States is 14-gauge copper wire. 14-gauge wire has a radius of $0.815\mathrm{mm}$. What is the electron drift speed if a $10\mathrm{A}$ current is carried in a 14-gauge wire?

What current does a $0.23\mathrm{V}/\mathrm{m}$ electric field create in an iron wire of $0.8\mathrm{mm}$ mm radius?