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To draw maximum current from a combination of cells, how should the cells be grouped
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Depends upon the relative values of external and internal resistance Solution:
Let each cell of emf ' \(\mathrm{E}\) ' and internal resistance ' \(\mathrm{r}\) '. There are \(\mathrm{n}\) such cells.The external resistance be ' \(R\) '.
If cells are connected in series :
current through 'R' \(=\frac{\mathrm{nE}}{\mathrm{nr}+\mathrm{R}}\)
If cells are connected in parallel :
current through ' \(\mathrm{R}\) ' \(=\frac{\mathrm{nE}}{\mathrm{r}+\mathrm{nR}}\)
Do draw a maximum current :
if \(\mathrm{nr}+\mathrm{R} > \mathrm{r}+\mathrm{nR}\) cells must be connected in parallel.
if \(\mathrm{r}+\mathrm{nR} > \mathrm{nr}+\mathrm{R}\) cells must be connected in series.
So it depends on the relative values of internal and external resistances.
If cells are connected in series :
current through 'R' \(=\frac{\mathrm{nE}}{\mathrm{nr}+\mathrm{R}}\)
If cells are connected in parallel :
current through ' \(\mathrm{R}\) ' \(=\frac{\mathrm{nE}}{\mathrm{r}+\mathrm{nR}}\)
Do draw a maximum current :
if \(\mathrm{nr}+\mathrm{R} > \mathrm{r}+\mathrm{nR}\) cells must be connected in parallel.
if \(\mathrm{r}+\mathrm{nR} > \mathrm{nr}+\mathrm{R}\) cells must be connected in series.
So it depends on the relative values of internal and external resistances.
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