A quantity of positive charge is distributed throughout the volume of a long nonconducting rod, which lies on the \(z\) axis and is centered at \(z=0\). The rod's radius \(R\) is much smaller than its length \(\ell\). For positions \(r \ll \ell\) and \(|z| \ll \ell\), calculate the electric fields inside and outside the rod as a function of the radial distance \(r\) from the rod's long central axis if the volume charge density is (a) \(ho_{0}\) and \((b) ho_{0}(1-2 r / R)\).