Building codes usually limit the current carried by a No.14 copper wire to 15 A.Many household circuits are wired with this size wire.What is the drift velocity of the electrons in this case? The diameter of this wire is 1.6 mm.Assume one conduction electron per atom in copper.The atomic weight of copper is 63.3 g/mol and its density is 8900 kg/m³.Avogadro's number is 6.022 × 10²³ molecules/mol and e = 1.60 × 10^-19 C. A)5.51 × 10^-4 m/s B)4.56 × 10^-4 m/s C)1.65 × 10^-3 m/s D)4.44 × 10^-2 m/s E)4.89 × 10^-5 m/s

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Quizplus · Accepted Answer

The drift velocity of electrons in a conductor can be calculated using the formula $v_d = \frac{I}{nAe}$, where $I$ is the current, $n$ is the number of charge carriers per unit volume, $A$ is the cross-sectional area of the conductor, and $e$ is the charge of an electron. Given the current (15 A), the diameter of the wire (1.6 mm), and the properties of copper (atomic weight, density, and Avogadro's number), we can calculate the number of conduction electrons per unit volume and then find the drift velocity. The correct calculation leads to the drift velocity being in the order of magnitude of $10^{-4}$ m/s, which matches choice A.

Building Codes Usually Limit the Current Carried by a No