Question 6: (1 point) Two power lines each have current flowing in them in the same direction. One line is carrying a current of 140 A, and the other line is carrying a current of 220 A. What is the magnetic force per metre between the two wires if they are a distance 0.6 m apart? N/m. is the force attractive or repulsive? (a) attractive (b) repulsive Question 7: (1 point) Find the magnetic field strength at the centre of a current loop of radius R = 39 cm, and current I = 2 A flowing through it. The loop is sitting on a xy-plane with the current flowing counterclockwise (as viewed from the positive z-axis). Is the field at the centre pointing in the positive or negative z-axis? (a) Positive (b) Negative Question 8: (1 point) A properly insulated, tightly wound, 56 cm solenoid is made from wire that is 0.28 mm in diameter. When steady current flows through the solenoid, a potential difference of 25 V is measured across the solenoid terminals. The field inside the solenoid is measured to be 0.45 mT, and the cross section of the solenoid is 3 cm. What is the resistivity of the wire material? 12 m