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 pro be. 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 c oils.
SUGGESTIONS:
EQUIPMENT: Helmholtz coils with power supply, Hall probe with projection slave meter.
SETUP TIME: 5 min.
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