Two identical cells give the same current through an external resistance of $2 \Omega$ regardless of whether the cells are connected in series or in parallel. The internal resistance of each cell is: (in $\Omega$)

$A$ resistance $R$ is connected to $n$ identical cells. If the current in the resistance is the same whether the cells are connected in series or in parallel,then the internal resistance $r$ of each cell is:

Two sources of equal $emf$ $E$ are connected in series with an external resistance $R$. The internal resistances of the two sources are $R_1$ and $R_2$ $(R_2 > R_1)$. If the potential difference across the source of internal resistance $R_2$ is zero,then the value of $R$ is:

An electric eel generates an electric current using biological cells called electroplaques. The eel has a total of $5000$ electroplaques arranged in $100$ rows. This arrangement is shown in the figure. Each electroplaque has an $emf$ of $0.15\ V$ and an internal resistance of $0.25\ \Omega$. The water surrounding the eel completes the circuit between its head and tail. If the resistance of the water is $500\ \Omega$,the electric current generated by the eel in the water is .......... $A$.

Two sources of equal $emf$ $(\varepsilon)$ are connected in series to an external resistance $R$. The internal resistances of the two sources are $R_1$ and $R_2$ $(R_2 > R_1)$. If the potential difference across the source having internal resistance $R_2$ is zero, then:

$10$ identical cells,each of potential $E$ and internal resistance $r$,are connected in series to form a closed circuit. What is the potential difference across any $3$ cells (in $E$)?