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Confused with current, voltage and resistance Watch

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    In physics unit one it states that in transmission lines:
    Transmission lines
    In step-up transformers the voltage is increased which reduces the current.
    Transmission lines have a high resistance and the current warms the transmission wires.

    In physics unit two it states that:
    As voltage increases current increases.
    As voltage increases resistance increases- so wouldn’t that increase the heat????
    REALLY confused!
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    Current heats up the transmission lines – voltage has increased, but current has decreased.
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    I thought an increase in voltage increased the current?
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    Ah, you use the equation

    power = current x voltage (P=IV)

    So, when you pass the same power through a power line...
    Say I = 10 A and V = 2 V
    P = 10 A x 2 V
    P = 20 W

    Now, if we step up the voltage – let's times it by 10 (remember that power will stay constant in this scenario)
    20 W = I x 20 V
    I = 1 A

    So current has decreased.

    That's the logic of power transmission anyway.
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    THANKS! MEANS A LOT! :p:)
 
 
 
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