Question

1. An aluminum wire having a cross-sectional area equal to 3.50 10-6 m2 carries a current of 6.50 A. The density of aluminum is 2.70 g/cm3. Assume each aluminum atom supplies one conduction electron per atom. Find the drift speed of the electrons in the wire. 0.000193452 Incorrect: Your answer is incorrect. The equation for the drift velocity includes the number of charge carriers per volume, which in this case is equal to the number of atoms per volume. How do you calculate that if you know the density and the atomic weight of aluminum? mm/s

2. The quantity of charge q (in coulombs) that has passed through a surface of area 1.95 cm2 varies with time according to the equation q = 8t3 + 3t + 6, where t is in seconds. (a) What is the instantaneous current through the surface at t = 1.05 s? A (b) What is the value of the current density? kA/m2

3. A lightbulb has a resistance of 285 Ω when operating with a potential difference of 130 V across it. What is the current in the lightbulb? mA

4.A portion of Nichrome wire of radius 4.00 mm is to be used in winding a heating coil. If the coil must draw a current of 8.10 A when a voltage of 120 V is applied across its ends, find the following. (Take the resistivity of Nichrome to be 1.50 ✕ 10−6 Ω · m.) (a) the required resistance of the coil Ω (b) the length of wire you must use to wind the coil m

Answer 1