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 $V$)

If the mass deposited in $30 \ s$ is $m$,what will be the $E.C.E$ of the copper voltameter?

What is the maximum number of $50 \, W - 100 \, V$ bulbs that can be connected in parallel to a battery of $120 \, V$ and $10 \, \Omega$ internal resistance so that they glow with maximum intensity?

Three identical batteries are connected in series with a wire of length $L$. The temperature of the wire increases by $T$ in time $t$. If $N$ such batteries are connected in series with a wire of the same material but length $2L$,the temperature increases by the same amount $T$ in the same time $t$. Find the value of $N$.

$A$ $16 \ \Omega$ wire is bent to form a square loop. $A$ $9 \ V$ battery with internal resistance $1 \ \Omega$ is connected across one of its sides. If a $4 \ \mu F$ capacitor is connected across one of its diagonals,the energy stored by the capacitor will be $\frac{x}{2} \ \mu J$,where $x = . . . . . . .$

$A$ battery with an internal resistance of $4 \Omega$ is connected to a circuit consisting of three resistors,$R$,$2R$,and $4R$,as shown in the figure. If the power generated in the circuit is maximum,then the magnitude of $R$ must be: (in $\Omega$)