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technical question, plz answer with explanation

Ques. An electric bulb is rated 220V and 100W.Wen it is operated on 110V,the power consumed will be? i)100W ii)75W iii)50W iv)25W

  • Arjun
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  • 3 Answers
  Answer
3 Answers

  • 25w

    0

  • 100w

    0

  • strongAnswer is option 4/strongbr /br /strongExplaination: /strongbr /br /Power br /br /P=I*V br /br /where I is the current, V is the voltage br /br /But ohms law says: br /br /I=V/R br /br /where R is the resistance br /br /so: br /br /P=V^2/R br /br /so we know that when operated at 220 volts, the power is 100w, so we can work out the resistance: br /br /R=220^2/100 br /br /R= 484 ohms. br /br /Now when operated at 110 volts: br /br /P=V^2/R br /=110^2/484 br /=25 Watts br /

    4
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