- #1
Alouette
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Homework Statement
A sphere of radius a has a charge density that varies with distance from its center d(r) = do*(r/a)**2.
Express the electric field as a function of distance from the center of the sphere r, a, do, and the permitivity of free space ez for each of the falling regions:
0<r<a
Homework Equations
[itex]\Phi[/itex]*dA= Q/[itex]\epsilon[/itex]o
The Attempt at a Solution
Using Gauss's Law I have E*4 [itex]\pi[/itex] r^2 = (4/5)*[itex]\pi[/itex]*do*r^3/ [itex]\epsilon[/itex]o
so E = (1/5)*do*r/[itex]\epsilon[/itex]o
But this isn't the right answer...help?