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JEE Main 2024 (27 Jan, Shift 2) · Power, Power Factor & Wattless Current

Power, Power Factor & Wattless Current question from JEE Main 2024 (27 Jan, Shift 2)

Q34JEE Main 2024 · 27 JAN · SHIFT 2Easy

Power, Power Factor & Wattless Current

A series LCR circuit with L=100π mH,C=10−3π FL = \frac{100}{\pi}\text{ mH}, C = \frac{10^{-3}}{\pi}\text{ F} and R=10 ΩR = 10\ \Omega, is connected across an ac source of 220 V,50 Hz220\text{ V}, 50\text{ Hz} supply. The power factor of the circuit would be ________.

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

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Answer: 1

  1. ω=2πf=100π\omega = 2\pi f = 100\pi rad/s.
  2. XL=ωL=100π×0.1π=10 ΩX_L = \omega L = 100\pi \times \frac{0.1}{\pi} = 10\ \Omega.
  3. XC=1ωC=1100π×10−3/π=10 ΩX_C = \frac{1}{\omega C} = \frac{1}{100\pi \times 10^{-3}/\pi} = 10\ \Omega.
  4. XL=XCX_L = X_C (resonance), so Z=RZ = R and cos⁡ϕ=RZ=1\cos\phi = \frac{R}{Z} = 1.
  5. Power factor =1= 1.
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