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JEE Advanced2011PhysicsAlternating CurrentActual

A series R - C circuit is connected to A C 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?

Options

  1. AI_R^A>I_R^B
  2. BI_R^A < I_R^B
  3. CV_C^A>V_C^B
  4. DV_C^A < V_C^B

Correct answer

B. I_R^A < I_R^B

Step-by-step solution

Z= R^2+X_C^2 = R^2+ ( 1 C )^2 In case (b) capacitance C will be more. Therefore, impedance Z will be less. Hence, current will be more. Option (b) is correct. Further, aligned V_C & = V^2-V_R^2 & = V^2-(I R)^2 aligned In case (b), since current I is more. Therefore, V_C will be less. Option (c) is correct. Correct options are (b) and (c). Analysis of Question (i) Question is moderately difficult. (ii) In my opinion problems of alternating currents are not very difficult. (iii) Topic of A C is small. One can feel co

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