Simple unanswered question (1 Viewer)

[Steven12]

alrite
so here the question


a cable has a resistance of 0.06ohm perkm. what is teh max distance over which 500000w of power can be transmitted with 10% of loss at 600kv?

so here is wat i did

P=VI 500000=600000*I
I=5/6(amps)

heat loss is P=I^2 R
p=(5/6)^2 * 0.06
p=0.7*0.06
P=0.042(watt) loss per km
500000*0.1=50000(w)

so if we were to lose 50000(watts) of power it will take
50000/0.042=1200000(km)

, did i just solve it? i was gonna ask you people. can anybody confirm if this is correct?

 

[abdo]

but didn't you just answer it?

 

[Steven12]

thats the thing, i was typing it out my question cos i couldnt do it. then it just clicked......


but is it right though? i thought the number was too big

 

[Xayma]

Yes I think for HSC physics that is correct. Anyway 5/6amp is nothing, and it wont be pushed through at that level in real life, transforming it isnt worth it.

However, what does the power loss cause, a loss of current or loss of voltage?

If it is a loss of current, then you should (in theory) redo it each km as each the current will change.

If it is voltage then it doesn't matter, although Im not sure which one it is.

 

[Steven12]

it doesnt say.it just says "10%loss at volage of 600kV "

it was in my half yearly and i dont think anyone solved it.

I dont think these kinda question will come up cos it wasnt in my text book
questions on this topic is usually the efficiency of transformers and stuff.