# Insulating Cylindrical Shell, Potential at edge

## Homework Statement

A long cylindrical insulating shell has an inner radius of a = 1.37 m and an outer radius of b = 1.60 m. The shell has a constant charge density of 2.70 10−9 C/m3. The picture shows an end-on cross-section of the cylindrical shell.

What is the magnitude of the electric field at a distance of r= 1.81 m from the axis?
5.76×101 N/C

What is the magnitude of the electric field at a distance of r= 1.52 m from the axis?
4.35×101 N/C

If we take the potential at the axis to be zero, what is the electric potential at the outer radius of the shell?

V=kdq/r

Va - Vb=∫E.da

## The Attempt at a Solution

∫ Q*(R^2 - r^2) / 2r *ε0 from the inner radius to the outer radius, my assumption was that since V equals the summation of electric field over the area enclosed, and that since potential was zero at the center, the potential would be equal to the difference in potential due to the electric field. Any insight or help is appreciated.