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Size: 1292
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Size: 1392
Comment:
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| Deletions are marked like this. | Additions are marked like this. |
| Line 1: | Line 1: |
| = Cavendish Spheres 5B30.20= | = Cavendish Spheres 5B30.20 = attachment:CavendishSpheres_5B3020.jpg |
| Line 5: | Line 7: |
| The charge producers (rods and fur) are located in [:ElectrostaticsCabinet:Electrostatics Cabinet], A1. | The 1000V DC Power Supply is located in [:ElectrostaticsCabinet:Electrostatics Cabinet], B2. The proof plane is located in [:ElectrostaticsCabinet:Electrostatics Cabinet], A1. |
| Line 9: | Line 13: |
| Connect the Faraday cage to the electrometer, grounding the outside cage. Connect two leads to the outside cage and simultaneously ground the inner and outer sphere. | Connect the Faraday cage to the electrometer, grounding the outside cage. Set the electrometer to measure 0V at half-range. |
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| The inside sphere is found to be uncharged, all of the charge having migrated to the outside sphere. | The inside sphere is found to be uncharged, all of the charge having migrated to the outside sphere. The only power law for electrostatic force that allows this to happen is the inverse square law. |
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| attachment:CavendishSpheres5B3020.jpg | |
| Line 28: | Line 34: |
attachment:CavendishSpheres5B3020.jpg |
Cavendish Spheres 5B30.20
attachment:CavendishSpheres_5B3020.jpg
The Cavendish Spheres, Faraday Cage, and electrometer are located in [:ElectrostaticsCabinet:Electrostatics Cabinet], B1.
The 1000V DC Power Supply is located in [:ElectrostaticsCabinet:Electrostatics Cabinet], B2.
The proof plane is located in [:ElectrostaticsCabinet:Electrostatics Cabinet], A1.
Cavendish used this experiment to prove the inverse square law of electrostatic force.
Connect the Faraday cage to the electrometer, grounding the outside cage.
Set the electrometer to measure 0V at half-range.
Rub the black rod on the fur. The black rod charges negative, as can be demonstrated by bringing it inside the inside cage.
Touch the black rod to the lead to the inside sphere. The inside sphere is now charged negative, while the outside sphere remains neutral.
Briefly connect the inside sphere to the outside sphere.
The inside sphere is found to be uncharged, all of the charge having migrated to the outside sphere. The only power law for electrostatic force that allows this to happen is the inverse square law.
Note: this writeup is incomplete as of 5/30/08. No one at UW physics seems to have successfully used this demonstration.
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