Chapter 4, Problem 4.13MCQ

For a single-phase, two-wire line consisting of two solid cylindrical conductors of same radius, r, the total circuit inductance, also called loop inductance, is given by (in H/m)

1. $2\times {10}^{-7}\ln \left(\frac{D}{r\text{'}}\right)$
2. $4\times {10}^{-7}\ln \left(\frac{D}{r\text{'}}\right)$

where $r\text{'}=e^{-\frac{1}{4}}r=0.778r$