Two long fixed parallel wires, A and B, are 10 cm apart in air and carry 40 A and 20 A respectively, in opposite directions. Determine the resultant field (a) on a line midway between the wires and parallel to them and (b) on a lone 8.0 cm from wire A and 18 cm from wire B. (c) What is the force per meter on a third long wire, midway between A and B and in their plan, when it carries a current of 5.0 A in the same direction as the current in A