Assignment:
Two long straight wires at separation d = 16.0 cm carry currents i1 = 3.61 mA and i2 = 3.00i1 out of the page.
(a) At what point on the x axis shown is the net magnetic field due to the currents equal to zero?
(b) If the two currents are doubled, is the point of zero magnetic field shifted toward wire 1, shifted toward wire2, or unchanged?
We know:
d = 16.0 cm = 1.6 x 10-1 m
i1 = 3.61 mA = 3.61 x 10-3 A
i2 = 3.00i1 = 3.00(3.61 mA) = 10.83 mA = 1.083 x 10-2 A
L for each conductor is infinite.