Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

a) A coaxial cable has acharged inner conductor (with charge +4.5 C and radius 3

ID: 1668701 • Letter: A

Question

a) A coaxial cable has acharged inner conductor (with charge +4.5 C and radius 3.364mm) and a surrounding oppositely charged conductor (with charge4.5 C and radius 9.605 mm).
The Coulomb constant is 8.98755 × 109 N · m2/C2.Assume the region between the conductors is air, and neglect endeffects. What is themagnitude of the electric field halfway between the two cylindricalconductors?
Answer in units of V/m.

b) What is the capacitance of this cable?
Answer in units of nF. a) A coaxial cable has acharged inner conductor (with charge +4.5 C and radius 3.364mm) and a surrounding oppositely charged conductor (with charge4.5 C and radius 9.605 mm).
The Coulomb constant is 8.98755 × 109 N · m2/C2.Assume the region between the conductors is air, and neglect endeffects. What is themagnitude of the electric field halfway between the two cylindricalconductors?
Answer in units of V/m.

b) What is the capacitance of this cable?
Answer in units of nF.

Explanation / Answer

The magnitude of the electric field halfway between the twoconductors is                                  E =ke /r = q /2oLr Where L = length of the cable    =..........?            r = radius = (a + b ) / 2            a = 3.364 mm            b = 9.605            q = 4.5C The capacitance of the spherical capacitor is              C = 2oL / ln(b/a)