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JEE Main 2023 (25 Jan, Shift 2) · Power, Power Factor & Wattless Current

Power, Power Factor & Wattless Current question from JEE Main 2023 (25 Jan, Shift 2)

Q47JEE Main 2023 · 25 JAN · SHIFT 2Medium

Power, Power Factor & Wattless Current

A series LCR circuit is connected to an AC source of 220 V, 50 Hz. The circuit contains a resistance R = 80Ω\Omega, an inductor of inductive reactance XL=70 ΩX_L = 70\ \Omega, and a capacitor of capacitive reactance XC=130 ΩX_C = 130\ \Omega. The power factor of circuit is x10\frac{x}{10}. The value of xx is:

Numerical answer type. Work it out, then open the answer.

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Answer: 8

  1. Z=802+(130−70)2=6400+3600=100 ΩZ = \sqrt{80^2 + (130 - 70)^2} = \sqrt{6400 + 3600} = 100\ \Omega.
  2. cos⁡ϕ=RZ=80100=810\cos\phi = \frac{R}{Z} = \frac{80}{100} = \frac{8}{10}.
  3. So x=8x = 8.
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