A plastic pipe has an inner radius of a = 35.00 cm and an outer radius of b = 71.00 cm. Electric charge is uniformly distributed over the region a < r < b. The charge density in this region is 30.00 C/m3 A)Calculate the magnitude of the electric field at r = 0.44 m. B)Calculate the magnitude of the electric field at r = 1.59 m. I need some help on where to begin. I know the e-field for cylindrical sym. is E=2kQin/rL I also know that Qin=charge density * Volume. How do I find the volume so I can find the Qin in both A and B?