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?

What is the electron current in a gold wire with a radius of $1.5\mathrm{mm}$ when the electron drift speed is $1.0\times {10}^{-4}\mathrm{m}/\mathrm{s}$?

Pure silicon at room temperature contains approximately 1.0 * 10^16 free electrons per cubic meter. (a) Referring to Table 25.1, calculate the mean free time t for silicon at room temperature. (b) Your answer in part (a) is much greater than the mean free time for copper given in Example 25.11. Why, then, does pure silicon have such a high resistivity compared to copper?

The two wires in FIGURE P27.63 are made of the same material. What are (b) the electron drift speed in the 2.0-mm-diameter segment of the wire?

The electron drift speed is 2.0 X 10⁻⁴ m/s in a metal with a mean time between collisions of 5.0 x 10⁻¹⁴ . What is the electric field strength?