Two identical batteries of emf ε = 9.17 V and internalresistance r = 0.279 Ω are to be connected to an external resistance R, either in parallel (Fig.27-52) or in series (Fig. 27-53). If R = 0.251Ω, what is the current i (in A) in the external resistance in the (a) paralleland (b) in the series arrangements?