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JEE Main 2023 (30 Jan, Shift 1) · Power, Power Factor & Wattless Current

Power, Power Factor & Wattless Current question from JEE Main 2023 (30 Jan, Shift 1)

Q50JEE Main 2023 · 30 JAN · SHIFT 1Medium

Power, Power Factor & Wattless Current

In a series LR circuit with XL=RX_L = R, power factor P1. If a capacitor of capacitance C with XC=XLX_C = X_L is added to the circuit the power factor becomes P2. The ratio of P1 to P2 will be:

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Answer: (a)

  1. XL=RX_L=R: Z=2RZ=\sqrt{2}R, P1=R/Z=1/2P_1 = R/Z = 1/\sqrt{2}.
  2. With XC=XLX_C = X_L the circuit is at resonance: Z=RZ=R, P2=1P_2=1.
  3. P1:P2=1:2P_1:P_2 = 1:\sqrt{2}, so the answer is (a).
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