An extremely long coaxial cable having a solid cylindrical inner conductor of radius 3.6 mm, surrounded by the outer cylindrical conductor with inner radius 7 mm and outer radius 9.7 mm. The area between the two conductors is filled with a wax resembling insulating material to keep the conductors from touching one other. The inner conductor carries a current 3.1 A, into the page, while the external conductor carries a current 2.4 A, out of the page.
i) Employ Ampere’s law to obtain an expression for the magnetic field as a function of r (the distance from central axis) at points within the outer conductor (R_2i < r < R_2o). Employ this expression to determine the magnetic field at 8.25 mm.
ii) Employ Ampere’s law to obtain an expression for the magnetic field as a function of r (the distance from the central axis) at points exterior the outer conductor (r > R_2o). Employ this expression to determine the magnetic field at 13.05 mm.