In a lab experiment, two long parallel wires are separated by a distance of $2\mathrm{.}45$ cm $.$ One wire carries a current of $1\mathrm{.}80$ A while the other carries a current of $3\mathrm{.}15$ A $.$ The currents are in opposite directions.

$($a$)$ What is the magnitude of the force per unit length $($in N$/$m$)$ that one wire exerts on the other?

$q,$ N$/$m

$($b$)$ Is the force attractive or repulsive?

attractive

repulsive

The magnitude is zero.