In the adjoining circuit,the $e.m.f.$ of the cell is $2 \, V$ and the internal resistance is negligible. The resistance of the voltmeter is $80 \, \Omega$. The reading of the voltmeter will be ............. $V$.

In an experiment on a circuit as shown in the figure, the voltmeter shows $8 \,V$ reading. The resistance of the voltmeter is,

Inside a superconducting ring,six identical resistors each of resistance $R$ are connected as shown in the figure. Imagine a battery of $emf$ $E$ connected between points $O$ and $1$,with its positive terminal connected to $O$.

In the circuit shown,the current through the $8\,\Omega$ resistor is the same before and after connecting the cell $E$. The value of $E$ is .................... $V$.

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 $N$.

$A$ voltmeter of very high resistance is connected in the circuit as shown in the figure. The voltage shown by this voltmeter will be . . . . . . . (in $V$)