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If two bulbs of 25 W and 100 W rated at 220 V are connected in series across 440 V supply. Will both the bulbs fuse? If not which one? |
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Answer» Solution :For an e electrical appliance `R=((V_(s)^(2))/(W))` `(R_(25))/(R_(100))=(W_(100))/(W_(25))=(100)/(25)=4"If"R_(100)-R, R_(25)=4R` `"in series,"V_(25)=(VxxR_(25))/(R_(25)+R_(100))440xx(4)/(5)=352V` `V_(100)=440-353=88V` From this it is clear that voltage across 100 W bulb is LESSER than specified (220 V). While across 25 W bulb is greater than (220V) so 25 W will FUSE. If the bulbs are connected in PARALLEL to 440 V supply, both bulbs will be fused because, applied voltage across each bulb is 440 V greater than specified voltage (220V) |
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