Two different configurations of n identical cells (each having electromotive force E and internal resistance r ) are shown in the figures. In Figure (a), the cells are connected in series across an external resistor of resistance R . In Figure (b), the same cells are connected in parallel across an identical resistor R . If the current measured by the ideal ammeter is found to be the same in both the configurations,

Step-by-step solution

For the series configuration in Figure (a), the equivalent electromotive force (emf) of n cells is nE and the equivalent internal resistance is nr . The current I_s through the circuit is given by: I_s = nE R + nr For the parallel configuration in Figure (b), the equivalent emf of n identical cells is E and the equivalent internal resistance is r n . The current I_p through the circuit is given by: I_p = E R + r n = nE nR + r Given that the current is the same in both configurations, we equate I_s and I_p : nE R +