Question

The minimum number of cells in mixed grouping required the produce a maximum currents of $1.5\text{A}$ through an external resistance of $30\Omega$ given the emf of each cell is $1.5\text{V}$ and internal resistance is $1\Omega$ is

• A. 120.00
• B. 120
• C. 120.0

Answer 1

Answer: (A), (B), (C)

In mixed grouping for maximum current,

$I=\frac{mnE}{mR+nr}[mR=nr]$

$I_{\text{max}}=\frac{nE}{2R}$ (or) $I_{\text{max}}=\frac{mE}{2r}$

$1.5=\frac{n1.5}{2\times 30}$

$1.5=\frac{m1.5}{2\times 1}$

$n=60;m=2$

$N=nm=60\times 2=120$