A Geiger tube consists of two elements, a long metal cylindrical shell and a long straight metal wire running down its central axis. Model the tube as if both the wire and cylinder are infinitely long. The central wire is positively charged and the outer cylinder is negatively charged. The potential difference between the wire and the cylinder is 0.95 kV. Suppose the cylinder in the Geiger tube has an inside diameter of 4.04 cm and the wire has a diameter of 0.550 mm. The cylinder is grounded so its potential is equal to zero.
a) What is the radius of the equipotential surface that has a potential equal to 525 V? Is this surface closer to the wire or to the cylinder? (cm)
b) How far apart are the equipotential surfaces that have potentials of 180 and 240 V? (mm)
c) Compare your result in Part (b) to the distance between the two surfaces that have potentials of 690 and 720 V, respectively. (mm)