# Power in delevering electricity to a factory

1. Jul 12, 2005

### melissa_y

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

2. Jul 12, 2005

### mathmike

you can also use the fact of p = I^2R = V^2 / R

3. Jul 13, 2005

### BobG

Voltage is equal to: V=IR

So, if the power is equal to $$P=RI^2$$, then it's also equal to $$P=VI$$

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 $$P=RI^2$$ to find out how much power is dissipated by the wire.

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