Three electric bulbs of $200\,W,\,\,200\,W$ and $400\,W$ are shown in figure. The resultant power of the combination is ................ $W$
$800$
$400$
$200$
$600$
A constant voltage is applied between the two ends of a metallic wire. If both the length and the radius of the wire are doubled, the rate of heat developed in the wire
In a building there are $15$ bulbs of $45\; \mathrm{W}, 15$ bulbs of $100\; \mathrm{W}, 15$ small fans of $10 \;\mathrm{W}$ and $2$ heaters of $1 \;\mathrm{kW}$. The voltage of electric main is $220\; \mathrm{V}$. The minimum fuse capacity (rated value) of the building will be: .......... $A$
Electric power is transmitted over long distances through conducting wires at high voltage because
The power rating of an electric motor which draws a current of $3.75\, amperes$ when operated at $200\, V$ is about
If resistance of the filament increases with temperature, what will be power dissipated in a $220\, V- 100\, W$ lamp when connected to $110\, V$ power supply