How do I calculate Volts per cm (V/cm) with the following given?

[HMS-776]

Homework Statement

How do I calculate Volts per cm (V/cm) with the following given?
Two coaxial tubes with 20kV placed across them.
Inner tube (actutally solid rod) has an OD of .5" and a length of 4"
Outer tube has an OD of 1.00" and a length of 4"

Homework Equations

The Attempt at a Solution

I was going to calculate the Area of the inner and outer tubes and convert them to cm, then divide the total area by the applied voltage? Somehow I don't think that is right?

 

[berkeman]

Homework Statement

How do I calculate Volts per cm (V/cm) with the following given?
Two coaxial tubes with 20kV placed across them.
Inner tube (actutally solid rod) has an OD of .5" and a length of 4"
Outer tube has an OD of 1.00" and a length of 4"

Homework Equations

The Attempt at a Solution

I was going to calculate the Area of the inner and outer tubes and convert them to cm, then divide the total area by the applied voltage? Somehow I don't think that is right?

I'm not understanding the problem statement. Why would you have two coax cables with a net voltage between them. Usually the shields of each coax will be at ground potential, or somebody is about to lose their job...

 

[HMS-776]

They are just coaxial tubes (one inside the other) which form a capacitor. Sorry if I explained that wrong.