1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Potential difference between the plates?

  1. Mar 16, 2009 #1
    1. The problem statement, all variables and given/known data

    A small electrically charged object is suspended by a thread between the vertical plates of a parallel-plate capacitor. The acceleration of gravity is 9.8 m/s^2.
    What is the potential difference between the plates? Answer in units of kV.

    Given: tetha = 14 degrees
    mass of the object = 152 mg
    q = 15 nC
    distance between the two plates = 5.6 cm


    2. Relevant equations

    I used the following:

    delta V = U/Q
    U = F x d


    3. The attempt at a solution


    I got U = 0.0000834176 Joules
    and I got V = 5561.1733333 V
    which is V = 5.561173333 kV

    but it's wrong.

    could someone please please tell me how to do it?
     
  2. jcsd
  3. Mar 16, 2009 #2

    LowlyPion

    User Avatar
    Homework Helper

    Welcome to PF.

    How did you resolve the force of gravity and the electrostatic force to determine your E field?
     
  4. Mar 16, 2009 #3
    Thank you.

    I got it.
    It took forever to finally get a reply from someone, so I asked someone else.

    What I did was Tcos(tetha) = (152x10^-6)(9.8)
    then, F=Tsin(tetha)

    Then I used, E=F/q
    Then I used, V=Ed, V/1000 (conversion from V to kV)

    My final answer is V = 1.386556241 kV

    And it's correct! :smile:
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Potential difference between the plates?
Loading...