Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Work performed on a proton between two charged plates

  1. Feb 4, 2010 #1
    1. The problem statement, all variables and given/known data
    A set of parallel conducting plates are seperated by .05 m. When the plates are fully charged to a potential difference of 20 V, how much work would have to be performed to move a proton from the negatively charged plate to the positively charged plate?

    My second question would be, is it negative work because its moving a positive charge towards the postive plate?


    2. Relevant equations
    V = k*q/r
    We = qV
    V = Ed



    3. The attempt at a solution
    20 * ? Im sorry i just dont understand this concept that well
     
  2. jcsd
  3. Feb 4, 2010 #2

    rl.bhat

    User Avatar
    Homework Helper

    Work = F*d*cosθ.
    Here force on the proton is E*q away from the positive plate.
    Proton is moving towards the +ve plate. So θ = 180 degrees.
    With these information find W.
     
  4. Feb 4, 2010 #3
    Wait...so I understand it being 180 degrees...but i do i need to use the protons charge as 1.6*10^-16 to find the force applied first?
     
  5. Feb 4, 2010 #4

    rl.bhat

    User Avatar
    Homework Helper

    Yes.
    The final formula will be
    W = V*q*cosθ.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook