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!

Voltage problem

  1. Sep 30, 2008 #1
    Can someone see what I am doing wrong here?

    A charge of q = +10-7 C is uniformly distributed on a spherical shell of radius 15 cm.

    (a) what is the E field just outside the shell.

    Isn't the E field given by k*Q/R^2 where Q is total charge (10e-7 C) and R, since it's immediately outside, .15m? So wouldn't I get 399.555 kV?

    (b)what's the magnitude of potential just inside and outside of the shell, and at the center?

    Isn't the E potential just k*Q/R, where R is the radius of the shell. And it's the same value everywhere inside because since the field is 0 so the potential must be constant. So wouldn't the answer be (8.99e9)*10e-7/.15 = 59933.333 V?

  2. jcsd
  3. Sep 30, 2008 #2


    User Avatar
    Homework Helper

    Looks ok, but check your units.

    Looks ok as well, if you substituted and computed the numbers properly.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Voltage problem
  1. Voltage problem (Replies: 1)

  2. Voltage Problem (Replies: 1)

  3. Problems with voltage (Replies: 15)