®
ES-9080A
012-07227G
Basic Electrostatics System
19
Conductive Conical Shape
1.
Remove the two conducting spheres. Connect the conductive
conical shape to the +2000 VDC port on the Electrostatics
Voltage Source.
2.
Use the proof plane to sample charge at the larger rounded end
and then at the narrow end.
Analysis
1.
Which end of the conical shape has the higher charge density?
2.
Why?
Conductive Hollow Sphere
1.
Remove the conducting conical shape. Connect the conductive
hollow sphere to the +2000 VDC port on the Electrostatics
Voltage Source.
2.
Use the proof plane to sample the charge on the outside surface
of the sphere. Then use the conductive knob end of the proof
plane to sample the charge inside the sphere.
Analysis
1.
How do the charges compare between the outside of the hollow
sphere and the inside of the hollow sphere?
Extra Things to Try
1.
To show that the charge on a conductor always resides on the
outside surface, bend a flexible sheet of metal into a cylinder.
Charge the cylinder and measure the charge density in the inner
and outer surfaces. Notice that charge is always on the outside.
2.
To show how the surface shape affects charge density, try
touching two charged proof planes together so that they are symmetrical around their
point of contact. Measure the charge on each. Next touch them in an asymmetrical manner
and measure the charge in each. Does one have more charge than the other? Which one?
(Be sure to eliminate stray charges from necks and handles, to prevent erroneous
readings.)
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Proof
plane
Conductive
conical
shape
Conductive
hollow sphere
Proof
plane
