Capacitance per unit length help

[budget76]

1. Homework Statement [/b]
You are planning to install a home video studio. A very important piece of information is missing from the specifications. You must find the capacitance per unit length for a coaxial cable. The cable has an inner radius of 1.1 {\rm mm} and an outer conductor 3.1 {\rm mm} in radius separated by polyethylene insulation that acts as a dielectric.

Homework Equations

(2pi*k*epsilon_0) / (ln(b/a))

The Attempt at a Solution

I attempted to use the above formula but do not know what k is, and found on a different website the formula without k so I attempted to use it and got 54.52, which was wrong.

thanks for any help

 

[kuruman]

Did you look up the dielectric constant of polyethylene? That's what k is.

 

[budget76]

I did not, I'll give it a try. Thank you