When a resistance of $2\,\Omega$ is connected across the terminals of a cell,the current is $0.5\,A$. When the resistance is increased to $5\,\Omega$,the current is $0.25\,A$. The $e.m.f.$ of the cell is ................. $V$.

The resistance of a voltameter is $2\,\Omega$. It is connected in series to a battery of $10\,V$ through a resistance of $3\,\Omega$. In a certain time,the mass deposited on the cathode is $1\,g$. Now,the voltameter and the $3\,\Omega$ resistance are connected in parallel with the battery. The increase in the deposited mass on the cathode in the same time will be .............. $g$.

For the previous objective,which of the following graphs is correct?

The readings of ammeters $A_1$ and $A_2$ will be respectively:

The potential difference across the terminals of the battery shown in the figure is .................... $V$. ($E = 10 \ V$,$r = 1 \ \Omega$,external resistance $R = 4 \ \Omega$) (in $V$)

Three resistances $A, B$ and $C$ having values $3R, 6R$ and $R$ respectively form a network as shown. When a potential difference is applied across the network,the thermal powers dissipated by $A, B$ and $C$ are in the ratio: