a) At one instant, the two conductors in a long household extension cord carry equal 1.95A currents in opposite directions. The two wires are 2.98mm apart. Calculate the magnetic field 42.4cm way from the middle of the straight cord, in the plane of the two wires.
b) At what distance is it one-tenth as large?
c) The center wire in a coaxial cable carries current 1.95A in one direction, and the sheath around it carries current 1.95A in the opposite direction. What magnetic field does the cable create at points outside?