During the 4.8 min a 5.2 A current is set up in a wire, how many (a) coulombs and (b) electrons pass through any cross section of the Wire's width? 4? (a) Number n Units 4} (b) Number l Units What is the current in a wire of radius R = 4.53 mm if the magnitude of the current density is given by (a) Ja = Jor/R and (b) Jb = J0(1 - r/R) in which r is the radial distance and Jo = 7.01 x 104 A/mz? (c) Which function maximizes the current density near the wires surface? 1} (a) Number Units 1} (b) Number n Units 1? (C) How long does it take electrons to get from a car battery to the starting motor? Assume the current is 260 A and the electrons travel through a copper wire with cross-sectional area 0.200 cm2 and length 0.880 m. The number of charge carriers per unit volume is 8.49 X 1028 ms. Number I Unit 4} Awire is 0.78 m long and 1.5 mm2 in cross-sectional area. It carries a current of 5.0 A when a 2.1 V potential difference is applied between its ends. Calculate the conductivity 0' of the material of which this wire is made. Number I Units 45 The figure gives the electric potential V(x) along a copper wire carrying uniform current, from a point of higher potential Vs = 11.0 uV at x = 0 to a point of zero potential at Xs = 3.20 m. The wire has a radius of 2.10 mm, and copper has a resistivity of 1.69 x 10-8 0.m. What is the current in the wire? V. V (u V) x (m) Number Units