$A$ large number of cells, each marked $(6 \,V, 0.5 \,\Omega)$, are available to supply current to a device of resistance $0.75 \,\Omega$, which requires a current of $24 \,A$. How should the cells be arranged to transmit power to the load using the minimum number of cells?

$n$ equal cells,each having emf $E$ and internal resistance $r$,are connected in a circuit with an external resistance $R$. If the same current flows in the circuit whether the cells are connected in series or in parallel,then:

It is easier to start a car engine on a hot day than on a cold day. This is because the internal resistance of the car battery

When cells are connected in parallel,then

Eels are able to generate current with biological cells called electroplaques. The electroplaques in an eel are arranged in $100$ rows,each row stretching horizontally along the body of the fish containing $5000$ electroplaques. The arrangement is shown below. Each electroplaque has an emf of $0.15\, V$ and internal resistance of $0.25\,\Omega$. The water surrounding the eel completes a circuit between the head and its tail. If the water surrounding it has a resistance of $500\,\Omega$,the current an eel can produce in water is about .............. $A$.

Consider a parallel combination of the cells shown in the figure. The potential difference between $B_1$ and $B_2$ is