Physics C question

Test Preparation AP Test Preparation
1

<p>ok, here is the question:</p>

<p>find the electric field of a distance z from the center of a spherical surface of radius r, which carries a uniform charge density sigma. treat the case z<r(inside the="" sphere)="" as="" well="" z="">r(outside of the sphere)> Express your answer in terms of the total charge Q on the sphere. (suggestion: use the law of cosines to write ro in terms of r and theta. be sure to take the positive sq rt) (also keep in mind that in spherical coordinates, unit vectors have nonzero derivatives)</r(inside></p>

<p>i drew a diagram</p>

<p>i found ro, which is sq rt (z^2 + r^2 - zrcos(theta))</p>

<p>i also have dl = dr r direction + r dtheta theta direction + r sin theta d phi phi direction</p>

<p>da =r62sintheta dthetadphi</p>

<p>dE = sigma/4piE0 da/ro squared</p>

<p>i need someone to help me with the calculus.</p>

<p>thanks in advance</p>

2

<p>Tipler says this "Of a charged solid spherel" (K)Q/r^2 for r>=R and "Of a chaged solid sphere" kQ/R^3*r for r<=R</p>

<p>What do you mean by spherical surface, is that like a thin spherical shell, tehn E=0 inside and R=kQ/R^2 outside</p>

3

<p>what the heck? ididtn even post that question...</p>