- #1

Tomtom

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I've learned at school that from P=V*I and V=IR, we can insert the second equation in the first, and get P=I^2*R. This equation shows (probably amongst more things) that the power emitted in a wire is the square of the current, and is why when transmitting large amounts of energy, high voltage is used, so that the current is small, and hence, power loss, too, is small.

However, by rearranging the second equation to I=V/R, I can insert it to give P=V^2/R. Now, why isn't this correct is the above situation? This should mean that we should have a large current, and small voltage.