I. Multiple Choice. (7 points) Choose the best answer and write the exact corresponding capitol letter in the blank 1) What magnetic pole is near the Hudson's bay in Canada? A) magnetic north B) magnetic south C) Geographic north pole D) Geographic south pole 2) The magnetic force on a current-carrying wire in a magnetic field is the weakest when magnetic field lines A) the current is at 45 .from the direction of the B) the current is in the direction of the C) the current is at a 180 angle with respect to the D) the current is perpendicular to the E) two of the above 3) In an RC circuit after how many RC values (assume capacitor is fully charged at t =0) the charge lost is 39% of its value at t=0? Assume the battery was removed from the circuit at t=0 and R and C make a complete circuit so current can continue. A) 3.5 B) 2.5 C) 4.5 D) 1 E) 1.5 4) Outside of a horse-shoe shaped magnet, the magnetic field lines are drawn to go into the magnetic pole. A) South B) North C) curved end D ) both A and C E) both B and C 5) A long, straight wire is carrying a current I as shown. What is the direction of the magnetic field at point P ? 0.04 8 p A) to the right of page B) to the left of the page C) toward the bottom of the page D) into the plane of the page E) out of the plane of the page 6) A 0.0150-m wire oriented horizontally between the poles of an electromagnet carries a direct current of 9.5 A. The angle between the direction of the current and that of the magnetic field is 25.0 as shown. If the magnetic field strength is 0.845 T, what is the magnitude and direction of the magnetic force on the wire between the poles? B 25.0 A) 1.17 N, upward B) 0.330 N, downward C) 0.0509 N, upward D) 0.120 N, downward E) 0.495 N, upward 7) Two long parallel wires placed side-by-side on a horizontal table carry identical size currents in opposite directions. The right wire carries current directly away from you. From your point of view, the magnetic field at a point exactly midway between the two wires A) points upward. B) points downward. C) points toward you. D) points away from you. E) is zero. Problem : Two long, straight wires are perpendicular to the plane of the paper as shown below (approximately). The wire on x-axis ( x = 60.00 cm) carries a current I1= 20.0 A while the wire on the y-axis ( at y = 40.00 cm) carries a current 12 =40.0 A. The direction of the current is as shown inside the circular cross section of the wire. .(a) (5 points) Determine the net magnetic field at a point on the x-axis with x = 80.0 cm. (b) (4 points) Draw the individual vectors and the the net vector showing the vector addition and confirm your answer in part (a). Choose an appropriate scale for the drawing of vectors. _y-axis X-axis