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MHT CET 2026 (14 May, Shift 2) · Power, Power Factor & Wattless Current

Power, Power Factor & Wattless Current question from MHT CET 2026 (14 May, Shift 2)

Q17MHT CET 2026 · 14 MAY · SHIFT 2Medium

Power, Power Factor & Wattless Current

An arc lamp requires a direct current of $10$ A at $90$ V to function. If it is connected to $220$ V (rms), $50$ Hz a.c. supply, the series inductor needed for it to work is nearly

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Answer: (b)

Lamp resistance $R = 90/10 = 9\ \Omega$ .
Needed impedance $Z = 220/10 = 22\ \Omega$ .
$X_L = \sqrt{22^2-9^2} = \sqrt{403} \approx 20\ \Omega$
$L = \frac{X_L}{2\pi f} = \frac{20}{100\pi} = \frac{1}{5\pi}$ H, so the answer is (b).

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