Walker, Halliday & Resnick — Circuits: Problem 6

6 Two identical batteries of emf \(\mathcal{E} = 10.0\text{ V}\) and internal resistance \(r = 0.200\text{ }\Omega\) are to be connected to an external resistance \(R\), either in parallel (Fig. 27-20) or in series (Fig. 27-21). If \(R = 2.00r\), what is the current \(i\) in the external resistance in the (a) parallel and (b) series arrangements? (c) For which arrangement is \(i\) greater? If \(R = r/2.00\), what is \(i\) in the external resistance in the (d) parallel arrangement and (e) series arrangement? (f) For which arrangement is \(i\) greater now?