A nonconducting spherical shell of inner radius R 1 and outer radius R 2 contains a uniform volume charge density ρ throughout the shell. Use Gauss's law to derive an equation for the magnitude of the electric field at the following radial distances r from the center of the sphere. Your answers should be in terms of ρ, R 1, R 2, r, ε0, and π.
(a) r < R 1

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