A capacitor is made from two hollow, coaxial, iron cylinders, one inside the other. The inner cylinder is negatively charged and the outer is positively charged; the magnitude of the charge on each is 18.5pC. The inner cylinder has a radius of 0.350mm, the outer one has a radius of 7.20mm, and the length of each cylinder is 17.0cmPart AWhat is the capacitance? Use 8.854

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Tavian

Physics

2 March, 19:49

A capacitor is made from two hollow, coaxial, iron cylinders, one inside the other. The inner cylinder is negatively charged and the outer is positively charged; the magnitude of the charge on each is 18.5pC. The inner cylinder has a radius of 0.350mm, the outer one has a radius of 7.20mm, and the length of each cylinder is 17.0cmPart AWhat is the capacitance? Use 8.854

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Corbin Webb · Answer 1

Answer: 3.12 * 10^12 F (3.12 pF)

Explanation: To calculate this capacitor of two hollow, coaxial, iron cylinders, we have to determine the potental differente between them and afeter that to use C=Q/ΔV

The electric field in th eregion rinner
By using the Gaussian law

∫E*ds=Q inside/εo

E*2*π*rinner^2*L = Q / εo

E=Q / (2*π*εo*r^2)

[Vab]=/int/limits^a_b {E} /, dr

where a and b are the inner and outer radii.

Then we have:

ΔV = 2*k * (Q/L) * ln (b/a)

replacing the values and using that C=Q/ΔV

we have:

C = L / (2*k*ln (b/a) = 0.17 / (2*9*10^9*3.023) = 3.12 pF