The value of the internal resistance of an ideal cell is:

Two cells,each of $e.m.f.$ $E$ and internal resistance $r$,are connected in parallel across an external resistor $R$. The maximum energy delivered to the resistor occurs when:

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 .......... $A$.

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

$A$ cell sends a current through a resistance $R$ for time $t$. Now the same cell sends current through another resistance $r$ for the same time. If the same amount of heat is developed in both the resistances,then the internal resistance of the cell is:

The internal resistance of a primary cell is $4\,\Omega$. It generates a current of $0.2\,A$ in an external resistance of $21\,\Omega$. The rate at which chemical energy is consumed in providing the current is .............. $J/s$.