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 Field and Potential

  1. Jul 14, 2017 #1
    1. The problem statement, all variables and given/known data
    An electric field is given by Ex = 2.2x + 5x2kNC-1. Find the potential difference between two points on the x axis at x = -2.0 m and x = 2.0 m

    2. Relevant equations
    ∫5x2+2.2x from -2 to 2

    3. The attempt at a solution
    I got the answer of 27V.

    Solution said - negative 27V

    Can someone please explain?
  2. jcsd
  3. Jul 14, 2017 #2
    Remember there is a negative sign in front of this integral since
    $$\mathbf{E}=-\nabla V$$.
  4. Jul 14, 2017 #3


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    ##\Delta V = -\int_{-2}^2{\vec{E} \cdot d\vec{s}}##
    You left out the negative sign.
  5. Jul 14, 2017 #4
    yes, sadly I recall it now.....

  6. Jul 14, 2017 #5
    I was so happy to have found the proper way of handling it, I didn't recall the formula!!
    Thanks all.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted