Vertical Capacitor Plates with Meter
Purpose
Students observe real-time capacitance changes as plate separation is varied and dielectric materials are inserted, directly verifying \(C = \varepsilon_0 \varepsilon_r A/d\). The demo can also be done with a projection electroscope instead of the capacitance meter.
Figure 1:
Plates at maximum separation: capacitance reads 3.5 pF.
Figure 2:
Plates moved closer: capacitance increases to 6.2 pF.
Figure 3:
Plates closer still: 12.1 pF, showing $C \propto 1/d$.
Figure 4:
Near-minimum plate separation: capacitance reaches 35.9 pF.
Figure 5:
Dielectric sheet inserted at the same plate separation: capacitance jumps to 44.3 pF, demonstrating $\varepsilon_r > 1$.
Demo Apparatus
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