OK. That helps. We've been trying to find equations and information that include distance. So the distance is included in the resistance calculation. Here is another example from the same test.heiber wrote:[Resistance changes with length yeah but I think you don't need length in this problem. Resistivity I believe measures resistance per length, but the resistance is given to you so I think the length can safely be ignored.

21. If a power plant is generating 100 MW, running on a 20 KV line (20 kilometers long), loses 10 MW of power after running along the line, how much resistance does the line have? (2 pts) Their answer:

1) Find Amps: P/V 100MW / 20KV= 5000A

2) Find Ohms: V/I= 20KV / 5MA= 4 ohms

My questions:

From Ohms Law, Resistance = Power / (Current * Current) or 100 MW / (20 KV * 20 KV) = 250 which is different. Why can't you use this equation and why is the answer different from above. All of the equations appear to be coming from the electrical formula wheel so would think it would work out either way.

Again - have information such as power loss of 10 MW and length of 20 kilometers that does not appear to even be used.

Thanks again.[/quote]

Bumping to see if I can get help understanding the solution to this problem. Thanks.