To get the maximum current from a parallel combination of $n$ identical cells,each of internal resistance $r$,connected to an external resistance $R$,which of the following conditions must be satisfied?

For an open circuit condition,what is the value of the terminal voltage of a cell?

Write the equation for the equivalent electromotive force (emf) of a series connection of cells.

Two identical cells send the same current in $2\,\Omega$ resistance,whether connected in series or in parallel. The internal resistance of the cell should be ............... $\Omega$.

Two cells,having the same $e.m.f.$ $E$,are connected in series through an external resistance $R$. The cells have internal resistances $r_1$ and $r_2$ $(r_1 > r_2)$ respectively. When the circuit is closed,the potential difference across the first cell is zero. The value of $R$ is

$A$ primary cell has an $e.m.f.$ of $1.5\,V$. When short-circuited,it gives a current of $3\,A$. The internal resistance of the cell is ............. $\Omega$.