Walker, Halliday & Resnick — Gauss' Law: Problem 48

48 Figure 23-46 shows two nonconducting spherical shells fixed in place. Shell 1 has uniform surface charge density \(+6.0\text{ \mu C/m}^2\) on its outer surface and radius \(3.0\text{ cm}\); shell 2 has uniform surface charge density \(+4.0\text{ \mu C/m}^2\) on its outer surface and radius \(2.0\text{ cm}\); the shell centers are separated by \(L = 12\text{ cm}\). In unit-vector notation, what is the net electric field at \(x = 2.0\text{ cm}\)?