A long, straight wire carries a current along the z-axis. One can find two points in the x-y plane such that

A straight wire carrying current is parallel to the y-axis as shown in Fig. The

A straight wire carrying current is parallel to the y-axis as shown in Fig. The

Four very long straight wires carry equal electric currents in the +z direction. They intersect the xy plane at (x,y)=(-a,0),(0,a),(a,0), and (0,-a) . The magnetic force exerted on the wire at position (-a,0) is along

Four very long straight wires carry equal electric currents in the +z direction. They intersect the xy plane at (x,y)=(-a,0),(0,a),(a,0), and (0,-a) . The magnetic force exerted on the wire at position (-a,0) is along

A long straight wire along z axis carries a current I in the negative z direction. The magnetic vector vecB at a point having coordinates (x, y) in the z = 0 plane is