Q. A series R-C circuit is connected to AC Voltage source. Consider two cases: (A) when C is without a dielectric medium and (B) when C is filled with dielectric of constant 4. The current $I_{R}$ through the resistor and voltage $V_{c}$ across the capacitor are compared in the two cases. Which of the following is/are true?
A) $I_{R}^{A} > I_{R}^{B}$
B) $I_{R}^{A} < I_{R}^{B}$
C) $V_{C}^{A} > V_{C}^{B}$
D) $V_{C}^{A} < V_{C}^{B}$
Explanation
(b) $Z = \sqrt{R^{2} + X_{C}^{2}}$
$= \sqrt{(R)^{2} + \left( \frac{1}{\omega C} \right)^{2}}$
In case (b) capacitance (c) will be more. Therefore, impedance Z will be less. Hence current will be more.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.