Timeline for How to interpret resistivity and its unit?
Current License: CC BY-SA 4.0
17 events
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| Oct 26, 2023 at 12:14 | history | edited | Philip Wood | CC BY-SA 4.0 |
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| Oct 26, 2023 at 11:06 | history | edited | Philip Wood | CC BY-SA 4.0 |
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| Oct 22, 2023 at 17:27 | history | edited | Philip Wood | CC BY-SA 4.0 |
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| Oct 22, 2023 at 16:32 | history | edited | Philip Wood | CC BY-SA 4.0 |
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| Oct 22, 2023 at 13:09 | comment | added | Philip Wood | @Nadav Har'El " it's just that it doesn't measure what we intend to measure..." So it's not a plausible candidate! I'm just arguing about words; we agree about the Physics. Kind regards. | |
| Oct 22, 2023 at 12:26 | comment | added | Nadav Har'El | Philip, I mean if you consider the wire to have a constant cross-section (e.g., a wire of a specific gauge), and measure total resistance R, it really does make sense to talk about "resistance per meter of the given wire", R/L, whose units are really $\Omega m^{-1}$. It's just that, indeed, is not "resistivity of copper" - it's "resistance per meter of a copper wire of the given gauge". So $\Omega m^{-1}$ is not nonsense - it's just that it doesn't measure what we intend to measure ("resistivity of copper"). | |
| Oct 22, 2023 at 12:10 | comment | added | Philip Wood | @Nadav Har'El "The thing is, this formula neglects the cross-section of the wire ..." That's why I don't consider it plausible. As you say, you can patch it up afterwards by taking account of the cross-sectional area, but $\Omega\ \text{m}^{-1}$ is blatantly false. | |
| Oct 22, 2023 at 10:46 | comment | added | Nadav Har'El | Here's a "plausible" explanation for $\Omega m^{-1}$ units: Let's say that you have a wire of length L meters, and measured its resistance to be be $R$ ohms. Now you can imagine that the "specific resistance" (resistance per unit length) is $R/L$, whose units are $\Omega m^{-1}$. The thing is, this formula neglects the cross-section of the wire, whose units are $m^2$ and factoring this in too gets you from $\Omega m^{-1}$ to $\Omega m$. | |
| Oct 22, 2023 at 10:35 | history | edited | Philip Wood | CC BY-SA 4.0 |
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| Oct 22, 2023 at 10:29 | history | edited | Philip Wood | CC BY-SA 4.0 |
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| Oct 22, 2023 at 8:48 | history | edited | Philip Wood | CC BY-SA 4.0 |
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| Oct 22, 2023 at 8:33 | history | edited | Philip Wood | CC BY-SA 4.0 |
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| Oct 22, 2023 at 8:15 | history | edited | Philip Wood | CC BY-SA 4.0 |
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| Oct 22, 2023 at 8:02 | history | edited | Philip Wood | CC BY-SA 4.0 |
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| Jun 20, 2018 at 16:04 | history | edited | Philip Wood | CC BY-SA 4.0 |
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| Jun 20, 2018 at 13:50 | history | edited | Philip Wood | CC BY-SA 4.0 |
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| Jun 20, 2018 at 13:16 | history | answered | Philip Wood | CC BY-SA 4.0 |