$A$ battery of emf $E$ and internal resistance $r$ is connected with an external resistance $R$ as shown in the figure. The battery will act as a constant voltage source if

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.

$A$ 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 .............. $V$.

The circuit in the figure shows two cells connected in opposition to each other. Cell $E_1$ has an $emf$ of $6 \ V$ and an internal resistance of $2 \ \Omega$. Cell $E_2$ has an $emf$ of $4 \ V$ and an internal resistance of $8 \ \Omega$. Find the potential difference between the points $A$ and $B$.

What will be the ratio of the equivalent electromotive force (emf) of two cells connected in series to the equivalent emf of two cells connected in parallel?

Who among the following scientists made the statement "Chemical change can produce electricity"?