Electromagnetic induction
PARTS AND MATERIALS
See previous experiment for instructions on
electromagnet construction.
CROSS-REFERENCES
Lessons In Electric Circuits, Volume
1, chapter 14: "Magnetism and Electromagnetism"
LEARNING OBJECTIVES
SCHEMATIC DIAGRAM
ILLUSTRATION
INSTRUCTIONS
Electromagnetic induction is the
complementary phenomenon to electromagnetism. Instead of
producing a magnetic field from electricity, we produce
electricity from a magnetic field. There is one important
difference, though: whereas electromagnetism produces a
steady magnetic field from a steady electric current,
electromagnetic induction requires motion between the
magnet and the coil to produce a voltage.
Connect the multimeter to the coil, and set
it to the most sensitive DC voltage range available. Move
the magnet slowly to and from one end of the
electromagnet, noting the polarity and magnitude of the
induced voltage. Experiment with moving the magnet, and
discover for yourself what factor(s) determine the amount of
voltage induced. Try the other end of the coil and compare
results. Try the other end of the permanent magnet and
compare.
If using an analog multimeter, be sure to
use long jumper wires and locate the meter far away from the
coil, as the magnetic field from the permanent magnet may
affect the meter's operation and produce false readings.
Digital meters are unaffected by magnetic fields.
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