Animation 1 | Animation 2 | Animation 3 | Animation 4

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The animation shows a top view of four wires and a galvanometer in the lab. Current flowing into the + terminal, i.e., counterclockwise, will deflect the meter to the right (positive voltage). During the time interval t = 2 s to t = 8 s a magnet is slowly pushed completely through the rectangle from below to above. The animation starts at t = 0 s and stops at t = 10 s.  Observe the meter reading (shown on the graph) during this simulation. In the animation of moving magnets, you see a side view of the process. Think of the left side of the gray loop as behind the computer screen and the right side as in front of the screen. Restart.

Which of the animations of moving magnets best matches what happens to create the graph shown?

Problem authored by Wolfgang Christian and modified by Melissa Dancy and Anne J. Cox.