The variable capacitance of an old radio tuner consists of four plates connected together placed alternately between four other plates, also connected together (Fig. $19-62$ ). Each plate is separated from its neighbor by 1.5 $\mathrm{mm}$ of air. One set of plates can move so that the area of overlap of each plate varies from 2.0 $\mathrm{cm}^{2}$ to $9.5 \mathrm{cm}^{2} .$ (a) Are these seven capacitors connected in series or in parallel? (b) Determine the range of capacitance values.