Electrostatics - probably a standard question

1. Apr 18, 2013

exuberant.me

Q) A solid non-conducting sphere of radius R carries non-uniform charge distribution with charge density ρ = ρs(r/R), where ρs is a constant. Show that
(a) the total charge on the sphere is Q = ∏ρsR3, and
(b) find the electric field inside the sphere.

Now first part (a) is fairly easy,
assumed a sphere of radius x and then after further integration got the result

But i need an idea for the second part..
since there is no symmetry so "Gauss" theorem is of no use applying...
I think i need an integration there as well. But can someone provide me an idea on how to continue further. Thanks in advance.

2. Apr 18, 2013

Staff: Mentor

There is a spherical symmetry.

3. Apr 18, 2013

barryj

How did you get the answer to part a. It seems incorrect to me.

4. Apr 18, 2013

barryj

Never mind, I got it.

5. Apr 20, 2013

exuberant.me

what about the electric field?

6. Apr 20, 2013

Dick

Use Gauss' theorem. Find the charge enclosed in a radius r'<R. Use integration.