A battery of 24 cells, each of emf 1.5 V and internal resistance 2 Ω is to be connected in order to send the maximum current through a 12 Ω resistor. The correct arrangement of cells will be

Suppose m rows are connected in parallel and each row contains n identical cells (each cell having E = 15 V and r = 2Ω)

For maximum current in the external resistance R, the necessary condition is

$\begin{array}{c}R=\frac{nr}{m}\\ \Rightarrow 12=\frac{n\times 2}{m}\Rightarrow n=6m\end{array}$

Total cells = 24 = n x m                      ..... (ii)

On solving equations (i) and (ii) n = 12 and m = 2