Gaussian surfaces can someone help walk me through this problem?

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    Gaussian Surfaces
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The discussion focuses on a physics problem involving Gaussian surfaces and electric fields related to a solid insulating sphere and a conducting spherical shell. The user seeks clarification on calculating the net charge enclosed by various Gaussian surfaces and the corresponding electric fields at specific points. Key points include the net charge calculation for a Gaussian surface of radius 16 cm, which should account for the positive charge of the sphere and the negative charge of the shell, resulting in a total of 1 μC. The user expresses confusion about the application of the electric field formula and acknowledges a potential miscalculation in their initial approach. The conversation emphasizes the importance of understanding charge distribution and its impact on electric fields in preparation for an upcoming test.
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Gaussian surfaces...need help...can someone help walk me through this problem??

A solid insulating sphere of radius 5 cm carries a net positive charge of 2 μC, uniformly distributed throughout its volume. Concentric with this sphere is a conducting spherical shell with inner radius 10 cm and outter radius 15 cm, having a net charge -1.00 μC. (a) Consider the spherical gaussian surface of radius 16.0 cm and find the net charge enclosed by this surface. (b) What is the direction of electric field at point D, to the right of the shell and at radius 16 cm. (c) Find the magnitude of electric field at point D. (d) Find the vector electric field at point C, and at radius 12 cm. (e) Consider the spherical gaussian surface through point C and find the net charge enclosed by this surface. (f) Consider a spherical gaussian surface of radius 8 cm and find the net charge enclosed by this surface. (g) Find the vector electric field at point B at radius 8 cm. (h) Consider a spherical gaussian surface through point A, at radius 4 cm and find the net charge enclosed by this surface. (i) Find the vector electric field at point A. (j) Determine the charge on the inner surface of the conducting shell. (k) Determine the charge on the outer surface of the conducting shell. (l) sketch a graph of the magnitude of the electric field versus r.

I would think that for (a) I would start with
E=k(Q+q)/r^2
=k([2]\mu[/C])/.16^2
=702345

I feel like this is completely wrong...can someone please help...I have a test coming up and this was the problem that my professor said we should be able to walk straight through with no problems and I'm completely lost.
 
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The formula is good, but surely Q+q is 2 - 1 = 1 μC
so your answer is twice what it should be.
 
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