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!

Homework Help: Electric potential distance problem?

  1. May 19, 2006 #1
    Hi everyone I need very badly some help with this problem please:

    A force of 0.053 N is required to move a charge of 39 µC a distance of 30 cm in an electric field. What is the size of the electric potential difference between the two points?

    Is the electric potential difference the force divided by q (whatever that is) divided by distance? That's what someone told me. I can't find q though. Is that even the right way to to it?

    I'm not really sure how to do this at all. I tried to do it for more than an hour yesterday but my teacher is TERRIBLE and I don't get it. The book doesn't really help either. Can someone solve it and guide me through it?

    Thanks a whole lot!
  2. jcsd
  3. May 19, 2006 #2


    User Avatar
    Homework Helper

    There are a few relationships involving voltage (or potential difference) V. The one you need here is [tex]W = QV[/tex] where V is the potential difference, Q is the charge and W is work done. W is the work required to move a charge Q against a potential difference of V.

    Now, use another relationship that you should know between work, force and distance to form an equation and solve for V.
  4. May 20, 2006 #3
    You should probably like to know the actual meaning of voltage. I personally like sentences.

    Voltage is the potential energy difference, per unit charge.
  5. May 20, 2006 #4


    User Avatar
    Homework Helper

    Sorry, sorry, sorry. I misread xXPhoenixFireXx's post. I missed the word "energy" in it, I thought he said "potential difference per unit charge" (which would be wrong). My apologies. I've deleted my post.
    Last edited: May 20, 2006
  6. May 20, 2006 #5
    haha hate it when that happens. I may as well delete mine as well 'cause I don't want to detract from the the purpose of the thread.
  7. May 20, 2006 #6
    Okay thanks.

    So exactly is q though? I'm confused. Is it 32 in the problem above or do I need to solve for it? If so what equation do I use?
  8. May 20, 2006 #7
    The charge Q is the 39 micro Coulombs that was given in the question
  9. May 20, 2006 #8
    Thanks. Do I need to conver it?
  10. May 20, 2006 #9


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Yes, you should convert it to Coulombs.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook