Region 2 Wire X Region I Wire Y 21 16. Two long, straight parallel wires X and Y are 15. A positively charged particle travels along the separated by a distance d and carry currents / and path shown in the figure above through region 1 21, as shown in the figure above. The force on and between two parallel plates in region 2. A wire X has magnitude F. If the current in each magnetic field exists in region 1, and one of the wire is both doubled and reversed in direction, plates in region 2 is at a higher potential than the which of the following is true of the magnitude other. What is the direction of the magnetic field and direction of the new force on wire X? in region 1, and which plate is at a higher Magnitude Direction potential in region 2 ? (A) F Unchanged Region 1 Plate at Higher Potential 2F Reversed (A) Out of the page Top plate 2F Unchanged (B) Out of the page Bottom plate 4F Reversed (C) Into the page Top plate (E) 4F Unchanged (D) Into the page Bottom plate (E) To the right Bottom plateQuestions 17-18 1 ! ;"' *IC \\\"- -0/ 1 N g L e Sphere | :D Sphese 2 & I | Three identical spheres are equally spaced from one another. Spheres 1 and 2 have charge +0. and sphere 3 has a charge of (, as shown in the figure above. Five different positions are labeled A, B, C, D, and E. Positions A, B, and C are all the same distance from sphere 3. Positions C, D, and E are all the same distance from sphere 2. All spheres and points lie in the same plane. 17. The electric potential is highest at position (A) A (B) B ) C (D) D (E) E 18. At which of the five positions are the horizontal and vertical components of the electric lield directed toward the left and the top of the page, respectively? (A) A (B) B (C) C (D) D (E) E 19. The magnetic field at a perpendicular distance r from a long, straight current-carrying wire is directly proportional to (A) r (B) r* (C) Vr ) V7 (E) In(r)