The $n$ rows each containing $m$ cells in series are joined in parallel. Maximum current is taken from this combination across an external resistance of $3 \,\Omega$ resistance. If the total number of cells used are $24$ and internal resistance of each cell is $0.5 \,\Omega$ then
A$m = 8,n = 3$
B$m = 6,n = 4$
C$m = 12,n = 2$
D$m = 2,n = 12$
Diffcult
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C$m = 12,n = 2$
c (c) Total cells = $m × n = 24 $.... $(i)$
For maximum current in the circuit $R = \frac{{mr}}{n}$
$==>$ $3 = \frac{m}{n} \times (0.5)$
$==>$ $m = 6n$ ..... $(ii)$
On solving equation $(i)$ and $(ii)$, we get $m = 12, n =2$
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