Two very long, straight, parallel
Two very long, straight, parallel wires carry currents that are directed perpendicular to the page, as in Figure P30.9. Wire 1 carries a current I1 into the page (in the –z direction) and passes through the x axis at x = +a. Wire 2 passes through the x axis at x = -2a and carries an unknown current I2. The total magnetic field at the origin due to the current-carrying wires has the magnitude 2μ0I1/ (2πa). The current I2 can have either of two possible values.
(a) Find the value of I2 with the smaller magnitude, stating it in terms of I1 and giving its direction.
(b) Find the other possible value of I2.