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Light bulbs

  1. Nov 27, 2011 #1
    1. The problem statement, all variables and given/known data
    A 220 volt circuit is fused for 30 amps. How many 60 watt incandescent soft whote light bulbs with tungsten filament burning at 3,0000 celsius can be used at the same time in the circuit without tripping the fuse?


    2. Relevant equations
    N/A

    3. The attempt at a solution
    (w/220)=30
    220=30 amps(w)
    220/30 amps=7.33 watts
     
  2. jcsd
  3. Nov 27, 2011 #2

    PeterO

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    Homework Helper

    At least have a look at this:

    http://en.wikipedia.org/wiki/Power_(physics)

    Go to the electric power section for some useful formulae. Those same formulae will be in your text book.
     
  4. Nov 27, 2011 #3
    Unfortunately i don't have a textbook to go with my homework...
     
  5. Nov 27, 2011 #4

    PeterO

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    Homework Helper

    See above.
     
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