$A$ car battery of $e.m.f.$ $12\,V$ and internal resistance $5 \times 10^{-2}\,\Omega$,receives a current of $60\,A$ from an external source. What is the terminal voltage of the battery (in $,V$)?

Four identical cells of emf $E$ and internal resistance $r$ are to be connected in series. If one of the cells is connected wrongly,the equivalent emf and effective internal resistance of the combination are

$A$ storage battery is connected to a charger for charging with a voltage of $12.5 \text{ V}$. The internal resistance of the storage battery is $1 \ \Omega$. When the charging current is $0.5 \text{ A}$,the $EMF$ of the storage battery is: ............... $\text{volts}$

When can the internal resistance of a cell be neglected? Explain.

To draw maximum current from a combination of cells,how should the cells be grouped?

If the potential difference across the internal resistance $r_1$ is equal to the $emf$ $E$ of the battery,then