
#1
Mar1411, 04:51 PM

P: 7

1. The problem statement, all variables and given/known data
The aluminum cable of a highvoltage transmission line carries a current 600A. The cable is 60km long, and it has a diameter of 2.5 cm. What is the power lost to Joule heating in this cable? 2. Relevant equations Should I use the equation V=1/(4piEo)integral(dq/r) to find the potential? And in saying that I also need to find the charge in order to find the potential difference? Do I have to use Gauss's Law to find the charge? 3. The attempt at a solution I know that the equation to find the power lost to joule heating is P=I^2R in order to find the resistance, I solved solved for the potential difference using V=1/(4piEo)(q/r), I assumed that since the cable is aluminum that the Q= 1.6x10^19C. my answer for potential difference is 1.2x10^7 which I know is wrong. 1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution 1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution 1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution 



#2
Mar1411, 06:06 PM

P: 7

I already answered the question. I had to look up resistivity for aluminum since the cable is made up of aluminum, and use the equation R=P(L/A). After finding the resistance. I was able to find out the power lost to Joule heating by using P=I^2(R). P=600^2(3.42)= 1.2X10^6W.



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