Two infinitely long parallel wires carry currents of equal magnitude. What is the resultant magnetic field due to the two wires at a point midway between the wires, compared with the magnetic field due to one of them alone, if the currents are (a) in the same direction and (b) in opposite directions?

Two infinitely long parallel

wires carry currents of equal magnitude. What is the

resultant magnetic field due to the two wires at a point

midway between the wires, compared with the magnetic

field due to one of them alone, if the currents are (a) in

the same direction and (b) in opposite directions?