A series RC circuit is connected to the same AC source under two conditions: (i) capacitor contains air as dielectric; (ii) capacitor contains mica as dielectric. Let V₁, V₂ be the capacitor voltages and i₁, i₂ the currents in cases (i) and (ii). Which statement is correct?
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Question

A series RC circuit is connected to the same AC source under two conditions: (i) capacitor contains air as dielectric; (ii) capacitor contains mica as dielectric. Let V₁, V₂ be the capacitor voltages and i₁, i₂ the currents in cases (i) and (ii). Which statement is correct?

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G1 Physics · Accepted Answer

Step 1: For a series RC circuit at fixed AC voltage, X(C)=1/(ωC) and I=V/√(R²+X(C)²). Step 2: Voltage across capacitor is V꜀=IX(C)=V X(C)/√(R²+X(C)²), an increasing function of X(C). Step 3: With mica dielectric, C rises and X(C) falls; hence V꜀ falls: V₁(air)>V₂(mica). Answer B. Final answer: (B) V₁ > V₂.