Coaxial cable is used in a huge number of places from household wiring to resear
ID: 1444424 • Letter: C
Question
Coaxial cable is used in a huge number of places from household wiring to research labs. Consider the typical coaxial cable shown below where a solid conductor with radius R_i is supported by insulating disks on the axis of a thin conducting tube with radius R_o. The central conductor and tube carry equal currents I in opposite directions. The currents are distributed uniformly over the cross sections of each conductor. Find an expression for the magnitude of the magnetic field at points outside the central, solid conductor but inside the tube (R_iExplanation / Answer
a) Using ampere's law,
B. L = u0 Iinside
for Ri < r < R0
B ( 2 pi r) = u0 I
B = (u0 I ) / (2pi r)
B) for r > R0
Iinside = I - I = 0
B = 0