# Homework Help: Method of images

1. Mar 22, 2006

### sachi

We have to find the capacitance and inductance of a pair of cylindrical conductors of radius r and at a distance d b away from eachother. I get the following expressions

C = 2Pi*epsilon0/ln(b/a)
L = Mu0/2Pi *ln(b/a)

We now have a cylindrical conductor a distance d above an infinite conducting plane. We are supposed to get the following expressions using the method of images:

C = Pi*epsilon0/ln(2d/r)
L = Mu0/Pi * ln(2d/r)

I can understand why the b goes to 2 d, but I can't see why we miss the factor of 2 from the numerator of C and the denominator of L.

thanks very much