In an L-R circuit L=(0.4/π ) and R = 30 Ω If the circuit has an alternating emf of 220 V at 50 cycle/s, the impedance and current in the circuit will be respectively :

Question

In an L-R circuit L=(0.4/π ) and R = 30 Ω If the circuit has an alternating emf of 220 V at 50 cycle/s, the impedance and current in the circuit will be respectively : (A)  50 Ω , 4.4 A  (B)  40.4 Ω , 5 A  (C)  3.07 Ω , 6.0 A  (D)  11.4 Ω , 17.5 A

Tardigrade Admin · Accepted Answer

In an L- R circuit, VR and VL, are mutually perpendicular to each other, hence impedence Z = √R2 + X2L ∴ Z = √R2 + (ω L)2 Given, R = 30 Ω, ω = 2π n = 2π × 50, L = (0.4/π) ∴ Z = √(30)2 + ((2π × 50 × 0.4/π))2 = 50 Ω Current in the circuit is given by i = (V/2) = (220/50) = 4.4 A

Q. In an L-R circuit $L = \frac{0.4}{π}$ and $R = 30 Ω$ If the circuit has an alternating emf of $220 V$ at $50$ cycle/s, the impedance and current in the circuit will be respectively :

$50 Ω, 4.4 A$

$40.4 Ω, 5 A$

$3.07 Ω, 6.0 A$

$11.4 Ω, 17.5 A$

Q. In an L-R circuit L=π0.4​ and R=30Ω If the circuit has an alternating emf of 220V at 50 cycle/s, the impedance and current in the circuit will be respectively :

50Ω,4.4A

40.4Ω,5A

3.07Ω,6.0A

11.4Ω,17.5A

In an L- R circuit, VR​ and VL​, are mutually perpendicular to each other, hence impedence Z=R2+XL2​​ ∴Z=R2+(ωL)2​ Given, R=30Ω,ω=2πn =2π×50,L=π0.4​ ∴Z=(30)2+(π2π×50×0.4​)2​=50Ω Current in the circuit is given by i=2V​=50220​=4.4A

Q. In an L-R circuit $L = \frac{0.4}{π}$ and $R = 30 Ω$ If the circuit has an alternating emf of $220 V$ at $50$ cycle/s, the impedance and current in the circuit will be respectively :

$50 Ω, 4.4 A$

$40.4 Ω, 5 A$

$3.07 Ω, 6.0 A$

$11.4 Ω, 17.5 A$