If a $2\, kW$ boiler is used everyday for $1$ hour, then the electrical energy consumed by the boiler in thirty days is .......... $units$.

$4$ bulbs marked $40\, W, 250\, V$ are connected in series with a $250\, V$ mains. The total power consumed is ............. $W$.

If voltage across a bulb rated $220 \,V, 100 \,W$ drops by $2.5 \%$ of its rated value, then the percentage of the rated value by which the power would decrease is (in $\%$)

Two electric bulbs have ratings $P_1 \text{ watt}, V \text{ volt}$ and $P_2 \text{ watt}, V \text{ volt}$. If they are connected in parallel to a $V \text{ volt}$ supply,the total power consumed will be:

The maximum power drawn from a source with electromotive force $E$ and internal resistance $r$ is given by:

An electric heater is marked with $220\, V$ and $1100\, W$. If it is used for $4\, hours$, the energy consumed in $kWh$ will be: