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Most Important Selected Qs for JEE AdvancedPhysicsAlternating Current

In a certain series LCR A.C. circuit it is found that X_L=2 X_C and phase difference between the current and voltage is / 4 . If now capacitance is made 1 / 4^ th & the inductance and resistance are doubled then which are not correct.

Options

  1. Avoltage will lead current by a phase of ⁻¹(1 / 2) .
  2. Bvoltage will lag behind current by a phase of ⁻¹(1 / 2) .
  3. Cvoltage will lag behind current by a phase of / 4 .
  4. Dvoltage and current will be in same phase.

Correct answer

C. voltage will lag behind current by a phase of / 4 .

Step-by-step solution

aligned & X_L=2 X_C & X_C^ =4 X_C & X_L^ =2 X_L & X_L^ -X_C^ =2 X_L-4 X_C=2 [X_L-2 X_C ]=0 aligned

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