$A$ heater draws a current of $2\,A$ when connected to a $250\,V$ source. The rate of energy dissipation is ............. $W$.

If voltage across a bulb rated $220 \text{ V} - 100 \text{ W}$ drops by $2.5\%$ of its rated value,the percentage of the rated value by which the power would decrease is ............... $\%$

There are $n$ number of identical electric bulbs,each designed to draw a power $P$ independently from the mains supply. If they are now joined in series across the same mains supply,what is the total power drawn by the combination?

An electric power line having a total resistance of $2 \ \Omega$ delivers $1 \ kW$ of power at $250 \ V$. The percentage efficiency of the transmission line is: (in $\%$)

Water boils in an electric kettle in $20$ minutes after being switched on. Using the same main supply,the length of the heating element should be . . . . . . to . . . . . . times of its initial length if the water is to be boiled in $15$ minutes.

In a building,there are $15$ bulbs of $45 \; W$,$15$ bulbs of $100 \; W$,$15$ small fans of $10 \; W$,and $2$ heaters of $1 \; kW$. The voltage of the electric main is $220 \; V$. The minimum fuse capacity (rated value) of the building will be: .......... $A$