I have V, and current for different lengths. I can get R with R=V/length. How does cross sectional area relate to the R vs. length graph?
Ok, thank you for your help. I am trying to find the cross sectional area. I think I'm confused about how to find the C.S.A because I wasn't given ρ (rho). The slope of my Resistance vs. Length graph is 8.7. I would have to manipulate --> R = ρℓ / A into A = ρℓ / R . I would have the values of R and ℓ but I would have two unknowns ρ and A.
- NCSLv 75 months agoFavorite Answer
It is not true that R=V/length.
You can get resistance R = V / I
where I ("eye") is the current (not l ("ell"), the length)
Furthermore, if you plot R vs length, you must hold the cross-sectional area constant in order to get a meaningful graph.
It might be better to explain what your objective is. I suspect that it is to calculate the resistivity ρ of the wire material.
R = ρℓ / A
so, if you plot R (vertical) vs ℓ/A (horizontal) the slope of the line shoud be the resistivity of the conductor.
If you find this helpful, please award Best Answer!
- Andrew SmithLv 75 months ago
Although I could give you the answer there is nothing in the question that gives any clues.
If this was an experiment you would be expected to take a number of pieces of wire of the same length but different diameters and discover the result.
If you take the theory you know that Resistance = resistivity ( a constant) * L/A
so that the gradient of the graph of R vs L is R/L = resistivity / A
ie the gradient of your graph is inversely proportional to the cross sectional area A