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

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:

$A$ battery of $24$ cells,each of emf $1.5\, V$ and internal resistance $2\, \Omega$,is to be connected to send the maximum current through a $12\, \Omega$ resistor. The correct arrangement of cells will be:

The potential difference across a cell and the current through it are shown in the graph. $A$ battery consists of $40$ such identical cells. The maximum current supplied by the battery through a load of $2.5\,\Omega$ is equal to .............. $A$.

In the following circuit, the current through $6 \Omega$ resistor is

When cells are connected in parallel,then