Question

When three identical bulbs of `60 W, 200 V` rating are connected in series to a `200 V` supply, the power drawn by them will be
A. 180 watt
B. 10watt
C. 20 watt
D. 60watt

Answer 1

If rated voltage=supply voltage then in series combination of bulbs
`(1)/(P_(eq))=(1)/(P_(1))+(1)/(P_(2))+(1)/(P_(3))+`.............
For this question
`(1)/(P_(eq))=(1)/(60)+(1)/(60)+(1)/(60)=(3)/(60)=(1)/(20)rArrP_(eq)=20` watt