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Power in delevering electricity to a factory

  1. Jul 12, 2005 #1
    A power station delivers 513kW of power to a factory through wires of total resistance of 2.72Ohm. How much less power is wasted if the electricity is delivered at 45200V rather than 13900V?

    I have no idea where to even begin except that I should find the intial current which is found by equation P=I^2R

    Please help me!
  2. jcsd
  3. Jul 12, 2005 #2
    you can also use the fact of p = I^2R = V^2 / R
  4. Jul 13, 2005 #3


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    Voltage is equal to: V=IR

    So, if the power is equal to [tex]P=RI^2[/tex], then it's also equal to [tex]P=VI[/tex]

    The current being delivered to the circuit comes from the Power and Voltage relationsip.

    To find how much power is lost, you have a new problem that uses the result of the first (you had to solve for I). You use the [tex]P=RI^2[/tex] to find out how much power is dissipated by the wire.

    Change the value of the voltage and repeat. Compare the two results.
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