There are two wires in parallel with the current traveling to the left in both. Find the direction of the torque on the top wire due to the bottom wire.
The Attempt at a Solution
I know I can use the right hand rule to find the direction of the b-field using the currents. So, at the top wire the b-field is pointing into the page. I'm not quite sure where μ is here since i thought that only applied to current loops.