In an LR circuit, the value of L is ( ( 0.4/ π)) H and the value of R is 30 Ω . If in the circuit, an alternating emf of 200 V at 50 cycle/s is connected, the impedances of the circuit and current will be

Question

In an LR circuit, the value of L is ( ( 0.4/ π)) H and the value of R is 30 Ω . If in the circuit, an alternating emf of 200 V at 50 cycle/s is connected, the impedances of the circuit and current will be (A) 11.40 Ω , 17.5 A (B) 30.7 Ω , 6.5 A (C) 40.4 Ω, 5 A (D) 50, Ω 4 A

Tardigrade Admin · Accepted Answer

Given, XL = ω L= 2 π fL = 2 π × 50 = ( 0.4/ π) = 40 Ω R = 30Ω Z = √ R2 + XL2 = √ (30)2 + (40)2 = 50 Ω irms = ( V rms/ Z) = ( 200/ 50) = 4 A

Q. In an $L R$ circuit, the value of $L$ is $(\frac{0.4}{π})$ $H$ and the value of $R$ is $30 Ω$ . If in the circuit, an alternating emf of $200 V$ at $50 cyc l e / s$ is connected, the impedances of the circuit and current will be

11.40 $Ω$ , 17.5 A

30.7 $Ω$ , 6.5 A

40.4 $Ω$ , 5 A

50, $Ω$ 4 A

Given, $X_{L} = ω L = 2 π f L$
= $2 π \times 50 = \frac{0.4}{π}$
= 40 $Ω$
R = 30 $Ω$
Z = $R^{2} + X_{L}^{2}$
= $(30)^{2} + (40)^{2} = 50 Ω$
$i_{r m s} = \frac{V _{r m s}}{Z}$
= $\frac{200}{50} = 4$ A

Q. In an LR circuit, the value of L is (π0.4​) H and the value of R is 30Ω . If in the circuit, an alternating emf of 200V at 50cycle/s is connected, the impedances of the circuit and current will be

11.40 Ω , 17.5 A

30.7 Ω , 6.5 A

40.4 Ω, 5 A

50, Ω 4 A