Induced Magnetic Fields and Force Between Two Opposing Current Loops Explained

[friendbobbiny]

Homework Statement

Except for the loops -- and the fact that current runs through them in opposite directions -- DISREGARD THIS DIAGRAM

Two wire loops have current traveling in opposite directions. My problem asks me to determine whether a force exists between both loops and, if so, then in which direction (attractive or repulsive). The correct answers are "yes" and "repulsive."

I want to understand why my logic isn't sound:

Homework Equations

Right hand rules[/B]

The Attempt at a Solution

1) Induced magnetic fields oppose each other
2) To evaluate the force applied on one loop, we need to:
a) Determine the direction of the magnetic field in the other loop
b) Apply the right-hand rules on one particle of the loop in question
3) The field running through the right hand loop points leftwards
a) a particle going around the loop experiences a radially outward force
b) all particles also experience radially outward forces
c) net force should cancel

 

[mfb]

Why radial outwards? The field is "circular" around the wire of loop 1, so it points in radial direction at the point where loop 2 is.

 

[friendbobbiny]

what do you meanby "circular" around the wire of loop 1? I take your description to mean:

1) Loop 1 creates a magnetic field
2) part of that magnetic field runs THROUGH loop 2
3) part of that magnetic field also runs around loop 2 on either side

 

[mfb]

Circular as in this image. If you imagine another wire nearby, running in the same direction, the wires attract or repel (based on the current direction).

 

[rude man]

You can also look at this as two magnets formed by the two loops. Since the currents oppose you will get two N or two S poles facing each other.