How do parallel conductors with currents in the same direction interact?

Question

How do two parallel conductors interact when their currents flow in the same direction?

Answer choices

1. They do not interact.
2. They attract each other.
3. They repel each other.
4. They first repel and then attract each other.
5. They first attract and then repel each other.

Explanation

Parallel conductors carrying currents in the same direction attract each other. Each conductor's magnetic field acts on the current in the other; the force direction can be determined using the left-hand rule.

Currents in opposite directions would produce repulsion.