1. Not finding help here? Sign up for a free 30min 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!

(Electric Charge and Electric Field)

  1. Jan 24, 2005 #1
    Please Help! (Electric Charge and Electric Field)

    Consider point a which is 70 cm north of a -3.6 µC point charge, and point b which is 84 cm west of the charge (Fig. 17-23).


    (a) Determine Vba = Vb - Va.
    V = ____
    (b) Determine Eb - Ea.
    Magnitude
    N/C = ____
    Direction = _____
    ° (counterclockwise from east is positive)

    Thanks for your help!
     

    Attached Files:

  2. jcsd
  3. Jan 24, 2005 #2
    At first I was thinking the first part had to do with the E = (KQ1)/r2 equation. You take that for both point a and b then subtract b-a to get the final velocity. That didnt seem to work, and I have been looking frantically for the past 30 min through my notes and have not been able to find an equation to start off this problem. I think I may be confusing test charges with normal charges.
     
  4. Jan 24, 2005 #3

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    That is not velocity,that is ELECTRIC POTENTIAL.And you shouldn't be using the formula for the electric field,but the formula for the electric potential...

    Daniel.
     
  5. Jan 24, 2005 #4
    Hmmm.... tried the equation V=Ed for potential but that didnt work. Am I using the right equation?
     
  6. Jan 24, 2005 #5

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    No,u should be using the electric potential created by an electric charge...

    [tex] V(r)=\frac{1}{4\pi\epsilon_{0}\epsilon_{r}} \frac{q}{r} [/tex]

    Daniel.
     
  7. Jan 24, 2005 #6
    Haven't had a chance to use that equation... can you explain where the e sub 0 and r come from please?
     
  8. Jan 24, 2005 #7

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    Those are electric permitivities.The one with the subscript "0" is the electric permitivity of vacuum.The one with the "r" subscript is the relative electric permitivity of the medium wrt the vacuum and is dimensionless...

    Irrelevant into discussion,really.U got a problem to solve...

    Daniel.
     
  9. Jan 24, 2005 #8
    I don't think it's irrelevant, I like to know all the values and what they are if I am going to use an equation. I just find it hard to believe, Axeman, you dont know what [tex] \epsilon_{0}[/tex] is since it seems you are in an electricity class.
     
  10. Jan 25, 2005 #9

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    What do you mean...??He SHOULD KNOW what [itex] \epsilon_{0} [/itex] is.Even if he's in High School...

    Daniel.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: (Electric Charge and Electric Field)
Loading...