A. A long straight cable with radius R carries a current uniformly distributed through its circular cross section. Find the self-inductance per unit length of the cable. Hint: find B inside and outside, then find energy everywhere and relate to the self-inductance (per unit length)
B. This cable is now modified to have an insulator wrapped around it and another thin conductor wrapped around the surface of the outer conductor. Find the self-inductance (per unit length) of the cable now.
C. Find the self inductance per unit length on a hollow cable where the current only runs on the surface of the outer conductor.
Show all calculations and explain the process involved in each step.