In the given circuit,an ideal voltmeter connected across the $10\,\Omega$ resistance reads $2\,V$. The internal resistance $r$ of each cell is ................... $\Omega$.

An infinite ladder network is arranged with resistances $R$ and $2R$ as shown. The effective resistance between terminals $A$ and $B$ is

If each resistor in the given figure is $9\, \Omega$,then the reading of the ammeter is .............. $A$.

An electrical circuit consists of ten $100 \,\Omega$ resistors. Out of these $10$ resistors,a group of $n_1$ resistors are connected in parallel and another group of $n_2$ resistors are separately connected in parallel. These two groups are then connected in series and this combination is connected to a voltage source of $100 \,V$. If the net current through the circuit is $2.5 \,A$,the values of $n_1$ and $n_2$ are:

$A$ $16 \ \Omega$ 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 $x = . . . . . . .$

The total current supplied to the given circuit by the battery is . . . . . . . (in $A$)