Halliday, Resnick & Walker — Capacitance: Problem 30

30 Figure 25-29 shows a variable “air gap” capacitor for manual tuning. Alternate plates are connected together; one group of plates is fixed in position, and the other group is capable of rotation. Consider a capacitor of \( n = 8 \) plates of alternating polarity, each plate having area \( A = 1.50 \text{ cm}^2 \) and separated from adjacent plates by distance \( d = 3.40 \text{ mm} \). What is the maximum capacitance of the device?