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: When is electric field zero and electric potential non zero

  1. Jan 13, 2013 #1
    1. The problem statement, all variables and given/known data

    Which one of the following statements about electric field strength and electric potential is
    A Electric potential is a scalar quantity.
    B Electric field strength is a vector quantity.
    C Electric potential is zero whenever the electric field strength is zero.
    D The potential gradient is proportional to the electric field strength.

    2. Relevant equations

    E=K Q/(R^2)
    V=K Q/R


    3. The attempt at a solution

    The answer is C

    If for example you had two positive charges of 3 coulombs a distance 4m apart.
    The electrostatic field at the midpoint would be zero. Effectively a positive charge at this point would be push by an equal force in both directions.

    However the Electric potential V would be 2*(k*(3/4)

    So you can have a zero E with a non zero V

    Is this logic ok
    Thanks for any help
  2. jcsd
  3. Jan 13, 2013 #2


    User Avatar
    Gold Member

    The electrical potential goes as 1/r, but your reasoning is correct. You could also consider the electric potential and electric fields associated with spherical conductors: Provided the conductor is closed, the E field inside is 0 but the potential is a constant.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook