(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A power station delivers 890 kW of power at 12 kV to a factory through wires with total resistance 5.0 [tex]\Omega[/tex].

How much less power is wasted if the electricity is delivered at 50 kV rather than 12 kV?

2. Relevant equations

eq-1) P = IV

eq-2) P = I^{2}R

Ohm's Law: V = IR

3. The attempt at a solution

I know the problem can be solved by solving for the current value in each case from eq-1, and plugging it in to eq-2 to calculate power loss.

Myrealquestion is why can't we apply Ohm's law to calculate I, and then plug it into eq-2? Why must we use eq-1 to get the current? Doesn't Ohm's law apply for all ohmic conductors, and since we have both the resistance and voltage of and across the conductor, can't we get the current that way?

Thanks!

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# Power loss in transmission lines

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