12. 12. The figure shows a current i through a wire in a uniform magnetic field, as well as the magnetic force acting on the wire. The field is oriented so that the force is maximum. In what direction is the field? [ ] (3.0) A -y : B C. X: D Z. 13. The figure shows four orientations, at angle e, of a magnetic dipole moment in a magnetic field. Rank the orientations according to the orientation energy of the dipole, greatest first. [ ] 0 10 le 0 (3.0) A 1 and 4 tie, then 2 and 3 tie; B 1 and 2 tie, then 4 and 3 tie; C, 1 and 3 tie, then 2 and 4 tie; D 2 and 3 tie, then 1 and 4 tie; 14, The figure here shows three long, straight, parallel, equally spaced wires with identical currents either into or out of the page. Rank the wires according to the magnitude of the force on each due to the currents in the other two wires, greatest first. [ ] 6 (3.0) A a, b, c; B a, c, b; C b, c, a; D c, b, a. 15. The figure here shows three equal currents i (two parallel and one antiparallel) and four Amperian loops. Along which of the loops Bºds has the smallest magnitude? [ ] Dd (3.0) A d; B d, a and c; C a and c; D b. 5 of 10