An electric bulb is rated $220\, V$ and $100\, W$. When it is operated on $110\, V$,the power consumed will be ....... $W$.

Draw a schematic diagram of a circuit consisting of a battery of three cells of $2\, V$ each,a $5\,\Omega$ resistor,an $8\,\Omega$ resistor,and a $12\,\Omega$ resistor,and a plug key,all connected in series. Include an ammeter to measure the current through the resistors and a voltmeter to measure the potential difference across the $12\,\Omega$ resistor. What would be the readings in the ammeter and the voltmeter?

Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then parallel in a circuit across the same potential difference. The ratio of heat produced in series and parallel combinations would be -

$A$ piece of wire of resistance $R$ is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is $R'$,then the ratio $R/R'$ is

$A$ battery of $9 \, V$ is connected in series with resistors of $0.2 \, \Omega$,$0.3 \, \Omega$,$0.4 \, \Omega$,$0.5 \, \Omega$,and $12 \, \Omega$ respectively. How much current (in $A$) would flow through the $12 \, \Omega$ resistor?

Name a device that helps to maintain a potential difference across a conductor.