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

In the given circuit,when the switch $S$ is closed,what is the current in amperes flowing through it?

Find the current in the $3\,\Omega$ resistance in the given circuit.

Two resistances of $400 \Omega$ and $800 \Omega$ are connected in series with a $6 \text{ V}$ battery of negligible internal resistance. $A$ voltmeter of resistance $10000 \Omega$ is used to measure the potential difference across the $400 \Omega$ resistor. The error in the measurement of potential difference in volts is approximately:

One end each of a resistance $r$,a capacitor $C$,and a resistance $2r$ are connected together. The other ends are respectively connected to the positive terminals of batteries $P$,$Q$,and $R$ having emfs $E$,$E$,and $2E$. The negative terminals of the batteries are then connected together. In this circuit,with steady current,the potential drop across the capacitor is:

In the circuit shown in the figure, the heat produced in the $5\, \Omega$ resistance is $10\, \text{cal/sec}$. The heat produced in the $4\, \Omega$ resistance is ................ $\text{cal/sec}$.