Two batteries in opposition are joined as shown. The internal resistance of $6 \mathrm{V}$ battery is $2 \mathrm{\Omega }$ and $4 \mathrm{V}$battery is $8 \mathrm{\Omega }$. The potential difference between the points $X$ and $Y$ is

The current in the resistance $R$ will be zero, if

In the circuit shown here $E_1=E_2=E_3=2 \mathrm{V}$ and $R_1=R_2=4 \mathrm{\Omega }$. The current flowing between points $A$ and $B$ through battery $E_2$ is

In the given circuit, the voltmeter records $5 \mathrm{V}$. The resistance of the voltmeter in $\mathrm{\Omega }$ is

In the circuit shown, $A$ and $\mathrm{V}$ are ideal ammeter and voltmeter respectively. Reading of the voltmeter will be