Question

Two long, straight, parallel wires 8.0 cm apart carry currents in opposite directions.
Use the right-hand source and force rules to determine whether the forces on the wires are attractive or repulsive.
a)Repulsive
b)Attractive

If the wires carry equal currents of 4.0 A, what is the magnetic field magnitude that each produces at the other's location?
B= microT

Use the result of part C to determine the magnitude of the force per unit length they exert on each other.
F/L = microT/m

Answer 1

Currents in parallel wires that are in the same direction result in an attractive force between the wires. If in opposite directions, they repel.

Use Ampere's Law for the B field and F = F = B I L for the force per length L

Answer 2

B = (4*pi*4A)/(2*pi*0.08m)