Two resistors $400 \, \Omega$ and $800 \, \Omega$ are connected in series across a $6 \, V$ battery. The potential difference measured by a voltmeter of $10 \, k \Omega$ connected across the $400 \, \Omega$ resistor is close to $.... \, V$.

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 potential difference across the terminals of the battery shown in the figure is ................. $V$. ($r$ = internal resistance of the battery)

In the network of resistors shown in the adjoining figure,the equivalent resistance between $A$ and $B$ is ............ $ohm$.

$A$ set of $n$ equal resistors,each of value $R$,are connected in series to a battery of emf $E$ and internal resistance $R$. The current drawn is $I$. Now,the $n$ resistors are connected in parallel to the same battery. The current drawn from the battery becomes $10I$. The value of $n$ is:

In how much time will one litre of ${H_2}$ be collected by a $5\, A$ current? (Given: $Z = 1 \times {10^{ - 8}}\,kg/C$ and density of ${H_2} = 0.09\,kg/{m^3}$)