Question

One of the common uses for a coaxial cable is to transmit radio frequencies. One such coaxial cable of length 33.0 m consists of an inner conducting cylinder with a radius of 1.15 mm and an outer conducting cylinder whose inner radius is 3.25 mm. The charges on the inner and outer cylinders are −7.10 µC and +7.10 µC, respectively.

(a) Determine the potential difference between the two cylinders along a path from the inner cylinder to the inside edge of the outer cylinder. Use the fact that the magnitude of the electric field at a distance r from the axis of the inner cylinder is given by E =

2kλ

r

where k is Coulomb's constant and λ is the linear charge density.
V

(b) If the space between the two cylinders is filled with air, determine the capacitance of the cable.
nF

Answer 1