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Calculating the voltage and electric field strength between two parallel plates

  1. Dec 26, 2009 #1
    1. The problem statement, all variables and given/known data

    - How much is the electrical voltage U between two evenly electrified parallel flat plates, distanced d = 1 cm, if the strength of electric field between them is E = 1 V / m? - - What is the strength of electric field to the left and to the right of each plate?
    - What is the force on the surface (area) unit between the two plates?
    - What are the voltage between the plates and the force on the surface unit as a result of doubling the distance between the two plates?
    - How is the strength of the electric field and force between the two plates altered (changed), if the voltage is maintained constant?
    Influencing constant is ε(0) = 8.85 × 10^-12 As / Vm.

    2. Relevant equations

    V= E*d
    F= Q*E
    V= Qd/ Aε(0)
    E= Q/ Aε(0)

    3. The attempt at a solution

    First part: How much is the electrical voltage U between two evenly electrified parallel flat plates?

    V= 1 V/m* 0.01 m= 0.01 V


    Are my calculations for the first part correct?

    And I really don't know how to approach the rest of the problem. Can someone please help me? Any hints?
     
    Last edited: Dec 26, 2009
  2. jcsd
  3. Dec 26, 2009 #2

    berkeman

    User Avatar

    Staff: Mentor

    Yes, V = 0.01V is correct for the first part. The other equation that you will need is Q = CV. That should give you what you need for the rest.
     
  4. Dec 27, 2009 #3
    Thank you for helping!

    Second part: What is the strength of electric field to the left and to the right of each plate?


    I need some help with this part. Any hints?

    Third part: What is the force on the surface unit between the two plates?

    E= ½ Q*V → Q= 2E/ V
    Q= 200 C

    F= Q*E= 200 N

    Fourth part: What are the voltage between the plates and the force on the surface unit as a result of doubling the distance between the two plates?

    d= 2 cm= 0.02 m

    V= d*E= 0.02 V
    Q= 2E/ V= 100 C
    F= Q*E= 100 N

    ARE MY CALCULATIONS CORRECT?

    Fifth part: How is the strength of the electric field and force between the two plates altered (changed), if the voltage is maintained constant?

    I need some help with this part. Any hints?

    Thank you for helping!
     
    Last edited: Dec 27, 2009
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