Field and Wave Electromagnetics 2nd Edition by David Cheng

Exercise 33

A capacitor consists of two coaxial metallic cylindrical surfaces of a length 30 (mm) and radii 5 (mm) and 7 (mm). The dielectric material between the surfaces has a relative permittivity r = 2 + (4/ r ), where r is measured in mm. Determine the capacitance of the capacitor.