Halliday, Resnick & Walker — Capacitance: Problem 36

36 Figure 25-34 represents two air-filled cylindrical capacitors connected in series across a battery with potential \(V = 10 \text{ V}\). Capacitor 1 has an inner plate radius of \(3.00 \text{ mm}\), an outer plate radius of \(1.5 \text{ cm}\), and a length of \(5.0 \text{ cm}\). Capacitor 2 has an inner plate radius of \(2.5 \text{ mm}\), an outer plate radius of \(1.0 \text{ cm}\), and a length of \(9.0 \text{ cm}\). The outer plate of capacitor 2 is a conducting organic membrane that can be stretched, and the capacitor can be inflated to increase the plate separation. If the outer plate radius is increased to \(2.5 \text{ cm}\) by inflation, (a) how many electrons move through point P and (b) do they move toward or away from the battery?