If power dissipated in the $9 \,\Omega$ resistor in the circuit shown is $36 \,W$,the potential difference across the $2 \,\Omega$ resistor is .......... $V$

The ammeter $A$ reads $2\, A$ and the voltmeter $V$ reads $20\, V$. The value of resistance $R$ is (Assuming finite resistances of ammeter and voltmeter).

What is the current in $A$ flowing through the given circuit?

One end of a Nichrome wire of length $2L$ and cross-sectional area $A$ is attached to an end of another Nichrome wire of length $L$ and cross-sectional area $2A$. If the free end of the longer wire is at an electric potential of $8.0\,V$,and the free end of the shorter wire is at an electric potential of $1.0\,V$,the potential at the junction of the two wires is equal to ............. $V$.

As shown in the figure,the voltmeter reads $2\,V$ across the $5\,\Omega$ resistor. The resistance of the voltmeter is $.......\,\Omega$.

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 $N$.