- #1

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I cannot quite picture what is going on in this problem. Is this a series circuit, which has 2 resistors, one is the wire, and the other one is to dissipate the power?

- Thread starter leolaw
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- #1

- 85

- 1

I cannot quite picture what is going on in this problem. Is this a series circuit, which has 2 resistors, one is the wire, and the other one is to dissipate the power?

- #2

chroot

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Science Advisor

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[tex]P = I^2 R[/itex]

Use Ohm's law to find how much current the wire carries at both 12 kV and 50 kV, then find how much power is lost to heat in the wire using that formula.

- Warren

- #3

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if I use ur method,

I first find the current through the wire (12kV): 12kV = I(3 ohms) = 4000A

and the power lost to heat: (4000)^2 * 3 = 4.8 * 10^7 W

And the current through the wire (50kV): 50kV = I (3ohms) = 16666.67A

and the power lost to heat: (16666.67)^2 * 3 = 8.3 * 10^8 W

The correct answer is 7500W, but if i substract these two numbers, they don's seem to give me the right answer

- #4

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I understand what the quesiton is asking for now.

Thx

Thx

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