PURPOSE: To investigate quantitatively the magnetic field of a pair of Helmholtz coils.
DESCRIPTION: Current is passed through a pair of Helmholtz coils and the magnetic field measured using an azimuthal Hall effect probe. The measured magnetic field value can be displayed by a projection meter slaved to the output of the Hall probe. The field of the Helmholtz coils can be seen to be very uniform over a large volume near the center of the coils.
Have your students do the calculation showing that spacing the coils at a distance equal to their radius provides the greatest volume of nearly uniform field by producing zero gradient in the axial component of the magnetic field at the center of the coils.
REFERENCES: (PIRA 5H15.46)
EQUIPMENT: Helmholtz coils with power supply, Hall probe with projection slave meter.
SETUP TIME: 5 min.
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