The amplitude of the induced emf
in
the motor-driven
coil can be used to determine the magnitude and direction of
the
magnetic field
of the earth (54 uT at an inclination of 69� in Oberlin) or of
the
big gray horseshoe
magnet (0.10 T at the center of the gap).
The coils have 1000 turns on a 1" square frame. The
rotation rate is 29 Hz.
We also
have a Rawson rotating coil
magnetometer.
NOTES
Make sure the contacts are clean,
use a shielded cable, and connect the frame of the motor to
the
oscilloscope ground.
