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Homework Help: Electric power

  1. Oct 23, 2007 #1
    1. The problem statement, all variables and given/known data
    a power station delivers 520kW of power to a factory through wires of total resistance of 3 ohms ,how much less power is wasted if the electricity is deliverd at 50,000V rather than 12,000V

    2. Relevant equations
    P=IV=I^R =V^/R

    3. The attempt at a solution

    I tried to use voltage and resistance to calculate power and compare that with 520kW ,but it did not make any sense.Please help me.
  2. jcsd
  3. Oct 23, 2007 #2
    Determine the current flowing at 12000 V and 520 kW. Power wasted I^2R. Next determine the current at 50000 V and 520 kW (it will be much less than earlier). Determine power wasted. Find the difference.
  4. Oct 23, 2007 #3
    Thanks a lot .
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