# Dot Convention in Magnetically Coupled Circuits MCQ’s

This set of Network Theory Multiple Choice Questions & Answers (MCQs) focuses on “Dot Convention in Magnetically Coupled Circuits”.

1. In the circuit given below, the input impedance ZIN of the circuit is _________

a) 0.52 – j4.30 Ω
b) 0.52 + j15.70 Ω
c) 64.73 + j17.77 Ω
d) 0.3 – j33.66 Ω

2. The switch in the circuit shown was on position X for a long time. The switch is then moved to position Y at time t=0. The current I(t) for t>0 is ________

a) 0.2e-125tu(t) mA
b) 20e-1250tu(t) mA
c) 0.2e-1250tu(t) mA
d) 20e-1000tu(t) mA

3. A series RLC circuit has a resonance frequency of 1 kHz and a quality factor Q = 100. If each of R, L and C is doubled from its original value, the new Q of the circuit is _____________
a) 25
b) 50
c) 100
d) 200

4. In the circuit shown, the voltage source supplies power which is _____________

a) Zero
b) 5 W
c) 10 W
d) 100 W

5. Initial voltage on capacitor VO as marked |VO| = 5 V, VS = 8 u (t), where u (t) is the unit step. The voltage marked V at t=0+ is _____________

a) 1 V
b) -1 V
c) 133 V
d) –133 V

6. In the circuit given below, for time t<0, S1 remained closed and S2 open., S1 is initially opened and S2 is initially closed. If the voltage V2 across the capacitor C2 at t=0 is zero, the voltage across the capacitor combination at t=0+ will be ____________

a) 1 V
b) 2 V
c) 1.5 V
d) 3 V

7. In the circuit shown below the current I(t) for t≥0+ (assuming zero initial conditions) is ___________

a) 0.5-0.125e-1000t A
b) 1.5-0.125e-1000t A
c) 0.5-0.5e-1000t A
d) 0.375e-1000t A

8. For a unit step signal u (t), the response is V1 (t) = (1-e-3t) for t>0. If a signal 3u (t) + δ(t) is applied, the response will be (considering zero initial conditions)?
a) (3-6e-3t)u(t)
b) (3-3e-3t)u(t)
c) 3u(t)
d) (3+3e-3t)u(t)

9. In the circuit given below, the switch S1 is initially closed and S2 is opened. The inductor L carries a current of 10A and the capacitor is charged to 10 V with polarities as shown. The current through C during t=0+ is _____________

a) 55 A
b) 5.5 A
c) 45 A
d) 4.5 A

10. An ideal capacitor is charged to a voltage VO and connected at t=0 across an ideal inductor L. If ω = 1LC√, the voltage across the capacitor at time t>0 is ____________
a) VO
b) VO cos(ωt)
c) VO sin(ωt)
d) VO e-ωtcos(ωt)

11. In the circuit given below, the capacitor initially has a charge of 10 C. The current in the circuit at t=1 sec after the switch S is closed will be ___________

a) 14.7 A
b) 18.5 A
c) 40 A
d) 50 A

12. In the circuit given below, the switch S1 is initially closed and S2 is opened. The inductor L carries a current of 10A and the capacitor is charged to 10 V with polarities as shown. The current through L during t=0+ is _____________

a) 55 A
b) 5.5 A
c) 45 A
d) 4.5 A

13. In the figure given below, what is the RMS value of the periodic waveform?

a) 26–√ A
b) 62–√ A
c) 43−−√ A
d) 1.5 A

14. In the circuit given below, the switch is closed at time t=0. The voltage across the inductance just at t=0+ is ____________

a) 2 V
b) 4 V
c) -6 V
d) 8 V

15. A rectangular voltage wave of magnitude A and duration B is applied to a series combination of resistance R and capacitance C. The voltage developed across the capacitor is ____________
a) A[1 – exp(-BRC)]b) ABRC
c) A
d) A exp(-BRC)