# Advanced Problems on Magnetically Coupled Circuits – 1 MCQ’s

This set of Network Theory Multiple Choice Questions & Answers (MCQs) focuses on “Advanced Problems on Magnetically Coupled Circuits – 1″.

1. Two coils are having self-inductance of 5 mH and 10 mH and a mutual inductance of 0.5 mH in a differential connection. The equivalent inductance of the combination is ___________
a) 14 mH
b) 5.85 mH
c) 6 mH
d) 6.15 mH

2. When two coupled coils of equal self-inductance are connected in series in one way the net inductance is 20 mH and when they are connected in the other way, the net inductance is 12 mH. The maximum value of net inductance when they are connected in parallel is __________
a) 2 mH
b) 5 mH
c) 4 mH
d) 6 mH

3. For the circuit given below, the effective inductance of the circuit across the terminal AB is ___________

a) 9 H
b) 21 H
c) 11 H
d) 6 H

4. For 2 coupled inductors LA and LB, their mutual inductance MLALB satisfies ____________
a) MLALB = \sqrt{L_A^2 + L_B^2}
b) MLALB > \frac{(L_A + L_B)}{2}
c) MLALB > \sqrt{L_A L_B}
d) MLALB ≤ \sqrt{L_A L_B}

5. For the circuit given below, the inductance measured across the terminals 1 and 2 was 15 H with open terminals 3 and 4. It was 30 H when terminals 3 and 4 were short-circuited. Both the inductors are having inductances 2H. The coefficient of coupling is ______________

a) 1
b) 0.707
c) 0.5
d) Inderminate due to insufficient data

6. The maximum value of mutual inductance of 2 inductively coupled coils with self inductance LA = 49 mH and LB = 81 mH is ______________
a) 130 mH
b) 63 mH
c) 32 mH
d) 3969 mH

7. The impedance seen by the source in the circuit is given by __________

a) (0.54 + j0.313) Ω
b) (4 – j2) Ω
c) (4.54 – j1.69) Ω
d) (4 + j2) Ω

8. In the circuit given below, the resonant frequency is ________________

a) \frac{1}{2π\sqrt{3}} Hz
b) \frac{1}{4π\sqrt{3}} Hz
c) \frac{1}{4π\sqrt{2}} Hz
d) \frac{1}{π\sqrt{2}} Hz

9. In the circuit shown below, I1 = 4 sin2t A and I2 = 0. The value of V1 is _______________

a) -16 cos2t V
b) 16 cos2t V
c) 4 cos2t V
d) -4 cos2t V

10. A parallel resonant circuit has a midband admittance of 20×10-3 S, quality factor of 60 and a resonance frequency of 200 k rad/s. The value of R is _____________
a) 50 Ω
b) 56.57 Ω
c) 80 Ω
d) 28.28 Ω

11. A series RLC circuit has R = 10 Ω, |XL| = 20 Ω and |XC| = 20 Ω is connected across an AC supply of 200 Vrms. The RMS voltage across the capacitor is ____________
a) 200∠-90° V
b) 200∠90° V
c) 400∠90° V
d) 400∠-90° V

12. In the circuit shown below, I1 = 4 sin2t A and I2 = 0. The value of V2 is _______________

a) 2 cos2t V
b) -2 cos2t V
c) 8 cos 2t V
d) -8 cos2t V

13. A circuit resonates at 1 MHz It also has a Q of 100. Bandwidth between half power points is _____________
a) 10 kHz
b) 100 kHz
c) 10 Hz
d) 100 Hz

14. For the circuit given below, the value of input frequency which is required to cause a gain equal to 1.5 is _____________