A resistor and an inductor are connected to an ac supply of 120 V and 50 Hz. The current in the circuit is 3 A. If the power consumed in the circuit is 108 W, then the resistance in the circuit is

Question

A resistor and an inductor are connected to an ac supply of 120 V and 50 Hz. The current in the circuit is 3 A. If the power consumed in the circuit is 108 W, then the resistance in the circuit is (A) 12 Ω (B) 40 Ω (C) √(52 × 28) Ω (D) 360 Ω

Tardigrade Admin · Accepted Answer

In an ac circuit, a pure inductor does not consume any power. Therefore, power is consumed by the resistor only. ∴ P=I v 2 R or 108=(3)2 R or R=12 Ω

Q. A resistor and an inductor are connected to an ac supply of $120 V$ and $50 Hz$ . The current in the circuit is $3 A$ . If the power consumed in the circuit is $108 W$ , then the resistance in the circuit is

$12 Ω$

$40 Ω$

$(52 \times 28) Ω$

$360 Ω$

In an ac circuit, a pure inductor does not consume any power. Therefore, power is consumed by the resistor only.
$∴ P = I_{v}^{2} R$
or $108 = (3)^{2} R$ or $R = 12 Ω$

Q. A resistor and an inductor are connected to an ac supply of 120V and 50Hz. The current in the circuit is 3A. If the power consumed in the circuit is 108W, then the resistance in the circuit is

12Ω

40Ω

(52×28)​Ω

360Ω