An infinite long straight conducting cylinderical shell of radius a is surrounded by a thin coaxial infinite conducing cylinderical shell of radius `b`. Assuming current flows uniformly through the cylinderical shell returns through the outer shell, the inductance per unit length for this arrangement is

Options

A. `(2 mu_(0))/(pi)ln((b)/(a))`
B. `( mu_(0))/(pi)ln((b)/(a))`
C. `( mu_(0))/(2pi)ln((b)/(a))`
D. `( mu_(0))/(4 pi)ln((b)/(a))`

Answer

C

Explanation

`underset(a)overset(b)int (mu_(0)i)/(2pi x)dx = (mu_(0)i)/(2pi) log((b)/(a)), L = (mu_(0))/(2pi) log((b)/(a))`