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idkwhatimdoing
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Homework Statement
The figure to the right shows two concentric spheres made from insulators. One has radius and the other has radius R1, and the other has radius R2. The inner sphere has a positive charge density, +ρ, while the insulator region between the inner and outer spheres has a negative charge density, −ρ.
Homework Equations
Gauss' Law
The Attempt at a Solution
a. I wrote expressions that represented each portion's charge densities, and set them equal to each other because the magnitudes of the charge densities are the same; I got 2.
b. I used a Gaussian sphere with radius r and enclosed a portion of the smaller sphere; solved
c. I used a Gaussian sphere with radius R2>r>R1. I expressed the charge of the small sphere as (4/3)π(R1)ρ. The other portion would be a sphere with radius r with a spherical cavity with radius R1 and charge density -ρ. I expressed its charge as (4/3)π(r^3-R1^3)(-ρ). I added these two together to get the enclosed charge, but I'm not sure how to express the flux in terms of E and dA. I know the negatively charged portion would have field lines entering the surface, and thus leading to a negative dot product, but would the positively charged sphere have an effect as well? Not sure what to do from here.
Any help would be appreciated