Question

$100$ cells, each of e.m.f. $5V$ and internal resistance $1\Omega$ are to be arranged so as to produce maximum current in a $25\Omega$ resistance. Each row is to contain equal number of cells. The number of
rows should be :-

• A. $2$
• B. $4$
• C. $5$
• D. $10$

Answer 1

The correct option is A $2$

Let m be the number of rows and n be the number of cells of each rows.
Thus, $mn=100\Rightarrow n=100/m$
For Max current $I=\frac{nr}{m}$
or $I=\frac{100r}{m^2}$
or $m^2=\frac{100\times 1}{25}=4\Rightarrow m=2$