A series R-C circuit is connected to an alternating voltage source. Consider two situations:(i) When capacitor is air filled.(ii) When capacitor is mi - Physics MCQ Physics | ExamTest.live

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

A $V_{a} = V_{b}$
B $V_{a} < V_{b}$
C $V_{a} > V_{b}$
D $i_{a} > i_{b}$

Solution & Step-by-step Explanation

Mica has a higher dielectric constant than air (K > 1).Capacity C increases (C_{b} > C_{a}).Reactance X_{C} = \frac{1}{ω C} decreases (X_{C b} < X_{C a}).Impedance Z = R^{2} + X_{C}^{2} decreases (Z_{b} < Z_{a}), so current i increases (i_{b} > i_{a}).Voltage across capacitor V_{C} = i X_{C} = \frac{V _{a ppl i e d}}{1 + ( R ω C ) ^{2}} .As C increases, the denominator increases, so V_{C} decreases. Thus V_{a} > V_{b} .

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

V_{a} = V_{b}

V_{a} < V_{b}

V_{a} > V_{b}

i_{a} > i_{b}

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

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