### Electricity and Magnetism

# Concentric Cylinders Capacitor

Problem by Herry Kwee

30 Nov 1999 00:00 WIB

A capacitor consists of two air-spaced concentric cylinders. The outer cylinder has a fixed radius b and the inner one a. The breakdown of air occurs at field strengths greater than Eb.

a. What is the inner radius a in terms of outer radius b for the potential of the inner cylinder to be maximum?

b. What is the inner radius a for the energy per unit length of the capacitor tor be maximum?

a. What is the inner radius a in terms of outer radius b for the potential of the inner cylinder to be maximum?

b. What is the inner radius a for the energy per unit length of the capacitor tor be maximum?