[填空题]
The variable capacitance of an old radio tuner consists of four pl+nol3cj)dr 4zates c59ixq u4azg u,onnected together placed alternately between four other plates, also connected together (Fig. Below). Each plate is separated from its neighbor by 1.5 mm of air. One set of plu49au5igz , qxates can move so that the area of overlap of each plate varies from $2.0cm^2$ to $9.5cm^2$
(a) Are these seven capacitors connected in series or in parallel?
(b) Determine the range of capacitance values. from pF to pF
