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A question about electrostatic

  1. Sep 3, 2016 #1
    1. The problem statement, all variables and given/known data


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    3. The attempt at a solution
    i dont understand what happens at the end, when the pail becomes negative charged!. my assumption is that since the positive charged nylon rod is making the electrons to closed together in one side of the pail by attraction, when the man takes off the nylon rod, the electrons in the pail will be distributed evenly on the surface of the can, but i am not sure!! help i been thinking about these for 3 days!!
     
  2. jcsd
  3. Sep 3, 2016 #2

    Student100

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    When he grounds it, he's giving the pail a path to electrons in the ground. Now what is happening in the pail when he holds the positive charged disc near it how are the electrons rearranging themselves within it?

    Have you read about charge by induction before?
     
  4. Sep 3, 2016 #3
    the electrons in the pail are to the side where the positive charged is, and the protons stay in the outer surface of the pail. So electrons will travel into the pail by grounding? to neutralize the outer protons. and when he releases the ground from the pail, the electrons that were on the side of the positively charged rod will travel through the wire to the sensor, resulting in a 0 charge reading. but i dont understand what happens at the end!? is the cage responsible?
     
  5. Sep 4, 2016 #4

    Student100

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    No.

    When he removes the positive charge, the negative charges distributed themselves over the surface of the pail, as to get as far from one another as possible. Since the pail is isolated, it now has a net negative charge.
     
  6. Sep 4, 2016 #5
    aaaaa of course!! now i understand!! thanks youu :,) =D
     
  7. Sep 4, 2016 #6
    so the electrons and the protons of the wire that is connected to the pail will have no influece in the results?
     
  8. Sep 4, 2016 #7

    Student100

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    Protons aren't moving, it's the conduction electrons, the free electrons of the conductor, that are moving.

    I'm assuming the red lead on the can is for the charge sensor, which probably has some kind of capacitor in it to actually make the measurement. You can probably regard it's effects as negligible here. The important part is realizing how induction charging works.
     
  9. Sep 4, 2016 #8
    aaaa thanks!! i usually always want to learn every little detail, but for now i will leave it alone jaja
     
  10. Sep 4, 2016 #9

    Student100

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    You don't have to leave early it alone, wanting to understands things is useful.

    Can you explain to me how charge by induction works now?
     
  11. Sep 4, 2016 #10
    yes!! so lets say i have a neutral object, and i make it to be close to an positive charged object, the electrons will come closer to the positive charged object by induction, similar to hydrogen bonding or dipole bond (from chemistry). So the electrons and protons of the original neutral object will be in different regions, electrons close to the positive charged object, protons near the surface. When I touch it, i will release electrons to cancel the protons from the pail (making the pail to be from positive to neutral.) now i release the positive charged object from the pail, and the rest of the electrons will distribute evenly to the surface area of the pail, making it negative. if the object was not be touched, then when releasing the positive charged object from the pail, it would return to its original neutral state. i didnt thought of how dipole bonds are similar to induction, would make things alot of easier for me! oh well! thanks :p
     
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