A variable air capacitor has 11 parallel movable plates interleaved with 10 fixed plates. The area of each plate is and the separation between consecutive plates is . What is the maximum capacitance of this multi-plate capacitor?
Answer and explanation
Correct answer: C.
- Step 1: A set of interleaved parallel plates forms parallel plate capacitor gaps connected in parallel.
- Step 2: Total number of plates is plates.
- Step 3: Number of active dielectric gaps is . Since all 20 gaps are connected in parallel, .
Answer
.
Why not the others: counts only 10 gaps; mistakenly multiplies by total plate count instead of ; counts only movable plates.
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