Coaxial cable has radius a of copper core and radius b of copper shield. Between there is an insulat

Waylon Mcbride 2022-05-10 Answered
Coaxial cable has radius a of copper core and radius b of copper shield. Between there is an insulator with specific resistivity ζ. What is the resistance of this cable with length L between the core and the shield?
First, I tried to solve this like this: d R = ζ l S
In our case the length is dr, and therefore I suppose that the area of this ring is 2πrdr: d R = ζ d r 2 π r d r The solution sheet says: d R = ζ d r 2 π r L
I know that something is wrong with my equation, because dr goes away and then I cannot integrate from a to b. But why is in the solution L instead of dr? As I understand problem instruction L= b-a. And therefore L=dr which doesn't make sense to me.
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Answers (1)

Layne Bailey
Answered 2022-05-11 Author has 16 answers
The area of your element is 2 π r L and the thickness of your element is d r
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