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A single-turn copper coil is connected to the Keithley Electrometer. When the coil is moved through the magnetic field of a magnetron magnet the electrometer will deflect, giving a reading of approximately 3mV.
As in H 1, the area through which the magnetic field "flows" increases as the loop is placed in the field. Thus, the magnetic flux changes over time, inducing an emf, which in turn induces a current. The current always flows in a direction that "cancels out" the change in magnetic flux. When the loop is fully in the magnetic field there is no current. When it is pulled back out of the field the induced current is in the opposite direction, this time opposing the decreasing magnetic flux. Thus, the induced emf is of opposite sign.
Row II, Row III
See chapter 29, starting page 993, University Physics, for information on electromagnetic induction.
Young, Hugh D., Roger A. Freedman, and A. Lewis Ford. Sears and Zemansky's University Physics: With Modern Physics, 12th ed. San Francisco: Pearson Addison-Wesley, 2008.