Two long parallel wires each carry 2.8A in the same direction, with their centers 1.8cm apart. Express your answer to two significant figures and include the appropriate units.
a) Find the magnitude of the magnetic field halfway between the wires.
b) Find the magnitude of the magnetic field at a point in the same plane as the wires, 1.8cm from one wire and 3.6cm from the other.
c) Find the magnitude of the force of interaction (per lenght) between the wires.
d) Tell whether the force is attractive or repulsive.