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!

Gauss law help

  1. Sep 14, 2005 #1
    ok i was flying through the homework no prob. then i hit this problem and i got an answer but i dont think its right.

    A uniformly charged sphere of radius R and volume charge density [tex] \rho_0[/tex] is adjacent to a uniformly charged infinite plane of surface charge density [tex] \sigma_0[/tex]. the charge densities are related by
    [tex] \sigma_0=\frac{\rho_0R}{2}[/tex]
    the center of the sphere is a distance d from the plane. Find two points, one inside the sphere and one outside the sphere where the electric field is oriented away from the plane at a 45 degree angle with respect to the z axis.[note these points are not on the axis] (in the figure the infinite plane lies in the xy plane )

    well i started this off by finding the electric field inside the sphere


    i then found the charge of the infinite plane via the pill box gaussian surface and came up with


    and breaking to components i got

    and by a similar approch i got

    like i said i dont think this is right, so if some one could help me out a bit that would be great

  2. jcsd
  3. Sep 15, 2005 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Mmmh. There's a problem here: you write [itex]\vec{E}= \mbox{a scalar}[/itex]. What are the directions of the E_P and E_S vectors? Write them in cartesian coordinate for a coordinate system centered on the sphere, and find the condition on E_p + E_s to be at 45°.

    Oh, and your field equations look wrong. The field inside the sphere is not uniform.
    Last edited: Sep 15, 2005
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Gauss law help
  1. Help with Gauss' law (Replies: 2)

  2. Help with Gauss' Law? (Replies: 1)

  3. Gauss's Law help! (Replies: 3)

  4. Gauss' Law Help (Replies: 20)