Voltage, electric field and potential energy for concentric shells

[tinesi]

1. Homework Statement
the a shell is charged Va=120v
shell b is grounded, Vb=0V

What is the voltage in the center of shells (vo)?
The electric field in the center of shells?
The potential energy in the center of shells?

Homework Equations

Vr=Va+(1/r-1/a)/(1/a-1/b)Vab (from integrals)
though I am not sure

The Attempt at a Solution

I assume that V0=Va=120V but I don't think so
I assume the field inside is 0

1/ro=1/0=0(?)
Vab=120v?
vo=-120v?
Eo=0?
U=0?

 

[Orodruin]

You have not reproduced a proper problem statement. Please spell out the problem exactly as given and give your detailed attempt.

 

[tinesi]

Sorry, my first time here. I have written more details.

 

[berkeman]

Welcome to the PF.

Homework Statement

the a shell is charged Va=120v
shell b is grounded, Vb=0V

What is the voltage in the center of shells (vo)?
The electric field in the center of shells?
The potential energy in the center of shells?

Are the concentric shells spherical or cylindrical? Can you show the integral that is used to calculate the E-field for this geometry?