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Dielectric between plates.

  1. Mar 29, 2017 #1
    1. The problem statement, all variables and given/known data
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    2. Relevant equations


    3. The attempt at a solution
    I couldnt find the V(x).I dont know ho to write the equation.I think that it will be constant cause potential betwwen two plates should be constant... ?
     
  2. jcsd
  3. Mar 29, 2017 #2

    cnh1995

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    What is the energy in the capacitor as a function of x?
    In other words, what is the capacitance as a function of x?
    How is force related to this energy?
     
  4. Mar 29, 2017 #3
    ##C_{eq}=(K+1)ε_0 \frac {xb} {d}## ? or maybe
    ##C=Kε_0 \frac {xb} {d}##
     
  5. Mar 29, 2017 #4

    cnh1995

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    I don't know the exact expression as I myself haven't worked it out yet, but check the answer at x=0. Is the capacitance zero at x=0?
     
  6. Mar 29, 2017 #5
    Yeah its
     
  7. Mar 29, 2017 #6

    cnh1995

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    No, it isn't.
    What is the capacitance for x=0?
     
  8. Mar 29, 2017 #7
    Theres no area when x=0
     
  9. Mar 29, 2017 #8

    cnh1995

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    How is this possible? Which area is considered for calculation of capacitance?
     
  10. Mar 29, 2017 #9
    You are taking a-x I am just x
     
  11. Mar 29, 2017 #10

    cnh1995

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    But that doesn't make the total capacitance zero. You need to draw the equivalent circuit and find the total capacitance as a function of x.
     
  12. Mar 29, 2017 #11
    I didnt understand
     
  13. Mar 29, 2017 #12

    cnh1995

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    What is the dielectric between the plates before the new dielectric (with constant k) is inserted?
    What is the capacitance when the new dielectric is not inserted at all?
     
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