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Question 3 1 pts A step-up transformer quadruples a primary voltage of 110 V. What is the ratio of the number of turns in its primary coil to the number of turns in the secondary coil? O 2:3 O 3:2 O 4:1 O 1:4 Question 4 1 pts A closed circular loop wire with a single turn and a radius 50 cm is located in a changing uniform magnetic field. If the emf induced in the loop is 400 mV, what is closest to the rate at which the magnetic field strength is changing? Assume the magnetic field is perpendicular to the plane of the circular loop. O 3.2 T/s O 0.5 T/s 1.35 T/s 0.83 T/sQuestion 1 1 pts The primary coil of a transformer has 150 turns and its secondary has 400 turns. If the power input to the primary is 120 W, we can expect the power output of the secondary to be 120 W 30 W 60 W 90W Question 9 1 pts A coil lies flat on a tabletop in a region where the magnetic field vector points straight up. The magnetic field vanishes suddenly. When viewed from above, what is the sense of the induced current in this coil as the field decreases? O oscillation back and forth O counter-clockwise O no motion O clockwise