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JEE Main202312 Apr 2023Morning ShiftPhysicsAlternating CurrentActual

Given below are two statements: Statement I : When the frequency of an AC source in a series LCR circuit increases, the current in the circuit first increases, attains a maximum value and then decreases. Statement II : In a series LCR circuit, the value of power factor at resonance is one. In the light of given statements, choose the most appropriate answer from the options given below.

Options

  1. AStatement I is incorrect but Statement II is true
  2. BBoth Statement I and Statement II are false
  3. CBoth Statement I and Statement II are true
  4. DStatement I is correct but Statement II is false

Correct answer

C. Both Statement I and Statement II are true

Step-by-step solution

When an a.c. voltage is applied in a series LCR circuit, the current is increased first, attains a maximum and then decreases. The formula to calculate the power factor is given by cos ϕ = R R 2 + X L 2 - X C 2       . . . 1 At resonance, X L = X C , Hence, cos ϕ resonance = 1 Thus, both the statements are true.

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