1. An infinitely long straight wire carries a current I1, and a wire loop of radius R carries a current 12 as shown in the Figure. If I1 = 412, and if the net magnetic field at the center of the circular loop is zero, how far is the center of from the straight wire? 2. Three infinitely long parallel straight wires lie in the xy-plane as shown in the Fig. The middle wire carries a current I to the left while the top and bottom wires each carry a current I to the right. If the wires are a distance d apart, what is the magnitude of the magnetic field at the midpoint P between the top and middle wire 3. Find magnetic field, B at P? Use i,=15A, i2 32A and d=5.3 cm 4. A horizontal wire carries a current I1 = 80 A dc. A second parallel wire 20 cm below it must carry how much current I2 so that it doesn't fall due to gravity? The lower wire has a mass of 0.12 g per meter of length. Find Iz? 11 =80A d = 20 cm FBA 12 = ? 5. a. A thin 10-cm-long solenoid used for fast electromechanical switching has a total of 400 turns of wire and carries a current of 2.0 A. Calculate the field inside near the center. b. A toroid has a total of 800 turns of wire and carries a current of 2.0 A. Calculate the field inside the toroid of radius 50 cm from the center. c. Each of the wires in the figures below carry the same current, either into or out of the page. Rank them by comparing magnetic field at the center of the square? d. The figure shows a circuit consisting of straight radial lengths and concentric circular arcs (either half or quarter circles of radii r, 2r, and 3r) and it carries the current I. What will be the magnetic field at the center