# 5H25.10 - Coil & Compass, Rods, Gaussmeter, & Tangent Galvanometer

Code Number:
5H25.10
Demo Title:
Coil & Compass, Rods, Gaussmeter, & Tangent Galvanometer
Condition:
Excellent
Principle:
Forces & Fields In and Around Coils
Area of Study:
Electricity & Magnetism
Equipment:
Gaussmeter - Model GM1A, Two Probes for Gaussmeter - (Axial and Transverse), 0 to 20 VDC Power Supply, Large 6' Diameter Coil, Steel Rods with Strings.
Procedure:

Hook the power supply to the coil and turn on the power.  The magnetic field outside and inside the coil can be mapped with the Gaussmeter and probes.  The axial probe will work better inside the coil.  Another way to demonstrate this is to set the coil on its side and hang two of the rods in the center of the coil.  With no power the rods will touch in the center of the coil.  Turn up the voltage and the rods will separate a distance that is proportional to the voltage.  Turn off the power and observe that the rods still retain some residual magnetism.

The tangent galvanometer is an antique instrument used to explore the magnetic field of the Earth.  A dip needle should also be used when doing this experiment/demonstration.

References:
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