Two electric bulbs whose resistances are in the ratio of $1 : 2$ are connected in parallel to a constant voltage source. The powers dissipated in them have the ratio:

In the circuit shown below,the resistances are given in $\Omega$ and the battery is assumed ideal with an emf equal to $3\,V$. The voltage across the resistance $R_4$ is ................. $V$.

Two resistors are connected in series across a battery as shown in the figure. If a voltmeter of resistance $2000 \,\Omega$ is used to measure the potential difference across the $500 \,\Omega$ resistor,the reading of the voltmeter will be ............... $V$.

The potential difference across the $8\ \Omega$ resistance is $48\ V$ as shown in the figure. The value of the potential difference across points $X$ and $Y$ will be ............... $V$.

In the given circuit,the internal resistance of the $18\,V$ cell is negligible. If $R_1 = 400\,\Omega$,$R_3 = 100\,\Omega$,and $R_4 = 500\,\Omega$,and the reading of an ideal voltmeter across $R_4$ is $5\,V$,then the value of $R_2$ will be ........... $\Omega$.

Three identical bulbs $B_1, B_2$ and $B_3$ are connected to the mains as shown in the figure. If $B_3$ is disconnected from the circuit by opening switch $S$,then the incandescence of bulb $B_1$ will