In the given circuit,if the current through the $10 \Omega$ resistor is $2.5 \text{ A}$,the value of $R$ is . . . . . . . (in $\Omega$)

In the following circuit,the $5 \, \Omega$ resistor develops $45 \, J/s$ due to the current flowing through it. The power developed per second across the $12 \, \Omega$ resistor is ............. $W$.

The total current supplied by the battery to the circuit is ............ $A$.

The potential difference between the points $P$ and $Q$ in the electric circuit shown is ................. $V$.

$A$ circuit containing five resistors is connected to a battery with a $12 \,V$ emf as shown in the figure. The potential difference across the $4 \,\Omega$ resistor is ........... $V$.

Two resistors of $100 \ \Omega$ and $200 \ \Omega$ are connected in series with a battery of $4 \ V$ and negligible internal resistance. $A$ voltmeter is used to measure the voltage across the $100 \ \Omega$ resistor,which gives a reading of $1 \ V$. The resistance of the voltmeter must be . . . . . . $\Omega$.