I need help with the following questions:

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The magnitude J of the current density in a certain wire with a circular cross section of radius R = 2.18 mm is given byJ = {3.13 X 108%? with J in amperes per square meter and radial distance r in meters. What is the current through the outer section bounded by r = [1933}? and r = R? Number n Units V When 98.7 V is applied across a wire that is 13 m long and has a 0.26 mm radius, the magnitude of the current density is 1.6 x 104 A/m. Find the resistivity of the wire. Number i UnitsIn the figure the ideal batteries have emfs 8, = 150 V and 82 = 50 V and the resistances are R1 = 3.0 0 and R2 = 2.0 0. If the potential at P is defined to be 140 V, what is the potential at Q? Q M R1 181 P Number i UnitsIn the figure below, what is the potential difference Va - V- between points d and c if 81 = 5.7 V, 82 = 1.6 V, R1 = R2 = 11 0, and Rg = 6.7 0, and the batteries are ideal? b R1 Re is R2 Number i Units v