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A series R-C circuit is connected to an alternating voltage source. Consider two situations: (A) When capacitor is air filled. (B) When capacitor is mica filled. Current through resistor is I and voltage across capacitor is V then:

1. VA > VB
2. VA = VB
3. VA < VB
4. VA ≠ VB

Correct answer: VA > VB

Solution

When the capacitor is air-filled (A), its capacitance is lower compared to when it is mica-filled (B) because mica has a higher dielectric constant. A lower capacitance leads to a higher capacitive reactance, which results in a higher voltage across the capacitor in case (A). Thus, VA > VB.

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