Answer Happy

Figure (a) shows, in cross section, three current-carrying wires that are long, straight, and parallel to one another. Wires 1 and 2 are fixed in place on an x axis, with separation d. Wire 1 has a current of 0.750 A, but the direction of the current is not given. Wire 3, with a current of 0.250 A out of the page, can be moved along the x axis to the right of wire 2. As wire 3 is moved, the magnitude of the net magnetic force #2 on wire 2 due to the currents in wires 1 and 3 changes. The x component of that force is Fex and the value per unit length of wire 2 is F2x/L2. Figure (b) gives F2x/L2 versus the position x of wire 3. The plot has an asymptote F2x/L2 = -0.642 UN/m as x — c. The horizontal scale is set by xs = 14.6 cm. What are the (a) magnitude and (b) direction (into or out of the page) of the current in wire 2? = 1.0 0.5 To EL (UN/m) 0 0 -0.5 x (cm) (b) (a) (a) Number i Units (b)