Current carrying conductors exert forces on each other Suppose the magnetic field at a particular point is B.  The force on a small current carrying wire dl situated at that point is found to be 

                                dF = I dl x B newton

Where I  is the electric current passing through the small conducting segment.  This is the magnetic analogue of the electric force law F = qE we notice that the force proportional to I, dl and B and is perpendicular to both dl and B.