Four identical cells of $EMF$ $E$ and internal resistance $r$ are connected as shown in the figure. Find the terminal voltage across any one cell.

$A$ current of $2\,A$ is flowing through a cell of $e.m.f.$ $5\,V$ and internal resistance $0.5\,\Omega$ from negative to positive electrode. If the potential of the negative electrode is $10\,V$,the potential of the positive electrode will be .............. $V$.

$A$ cell of emf $10 \text{ V}$ and internal resistance $3 \Omega$ is connected in parallel with another cell of emf $7 \text{ V}$ and internal resistance $\frac{3}{5} \Omega$,such that their positive terminals are joined together and their negative terminals are joined together. Their combined positive terminal is joined with the negative terminal,and their combined negative terminal is joined with the positive terminal of a third cell of emf $20 \text{ V}$ with internal resistance $2 \Omega$. The combination can be replaced by a battery of emf $E$ and internal resistance $r$. The values of $E$ and $r$ are respectively:

$A$ battery consists of $5$ rows of cells,each row containing $10$ cells in series. This battery is connected in parallel to an external resistor of $20 \,\Omega$. If each cell has an $emf$ of $1.5 \,V$ and an internal resistance of $1 \,\Omega$,what is the current $i$ flowing through the external resistor (in $,A$)?

For a cell with non-zero (finite) internal resistance,write the relation between the terminal voltage $(V)$ and the electromotive force $(E)$ of the cell.

Two cells of emf $E_{1}$ and $E_{2}$ are joined in opposition (such that $E_{1} > E_{2}$). If $r_{1}$ and $r_{2}$ are the internal resistances and $R$ is the external resistance,then the terminal potential difference across the external resistance $R$ is: