# Problems Involving Standard Time Functions MCQ’s

This set of Network Theory Multiple Choice Questions & Answers (MCQs) focuses on “Problems Involving Standard Time Functions”.

1. In the circuit given below, Z1 = 10∠-60°, Z2 = 10∠60°, Z3 = 50∠53.13°. The Thevenin impedance as seen from A-B is _____________

a) 56.5∠45°
b) 60∠30°
c) 70∠30°
d) 34.4∠65°

2. In the circuit given below, the value of Z which would cause parallel resonance at 500 Hz is ___________

a) 125 mH
b) 34.20 μF
c) 2 μF
d) 0.05 μF

3. A voltage waveform V (t) = 12t2 is applied across a 1 H inductor for t≥0, with initial current through it being 0. The current through the inductor for t greater than 0 is ___________
a) 12t
b) 24t
c) 12t3
d) 4t3

4. In the circuit given below, the current source is 1∠0° A, R = 1 Ω, the impedances are ZC = -j Ω and ZL = 2j Ω. The Thevenin equivalent looking across A-B is __________

a) 2–√∠0 V, (1+2j) Ω
b) 2∠45° V, (1-2j) Ω
c) 2∠45° V, (1+j) Ω
d) 2–√∠45° V, (1+j) Ω

5. A voltage having the waveform of a sine curve is applied across a capacitor. When the frequency of the voltage is increased, what happens to the current through the capacitor?
a) Increases
b) Decreases
c) Remains same
d) Is zero

6. An inductive coil connected to a 200 V, 50 Hz AC supply with 10 A current flowing through it dissipates 1000 W. The value of the impedance Z and Reactance XL are respectively ____________
a) 10 Ω and 15 Ω
b) 20 Ω and 17.3 Ω
c) 17.3 Ω and 20 Ω
d) 15 Ω and 10 Ω

7. A periodic rectangular signal X (t) has the waveform as shown below. The frequency of the fifth harmonic of its spectrum is ______________

a) 40 Hz
b) 200 Hz
c) 250 Hz
d) 1250 Hz

8. An inductive coil connected to a 200 V, 50 Hz AC supply with 10 A current flowing through it dissipates 1000 W. Which of the following will have least value?
a) Resistance R
b) Reactance XL
c) Impedance Z
d) Reactance XC

9. A relay coil having voltage of magnitude 210 V and frequency 50 Hz is connected to a 210 V, 50 Hz supply. If it has resistance of 50 Ω and an inductance of 0.2 H, the apparent power is _____________
a) 549.39 VA
b) 275.6 VA
c) 157 VA
d) 187 VA

10. A 10 V is connected across a load whose V-I characteristics is given by 7I = V2 + 2V. The internal resistance of the battery is of magnitude 1Ω. The current delivered by the battery is ____________
a) 6 A
b) 5 A
c) 7 A
d) 8 A

11. A rectifier type AC voltmeter consists of a series resistance R, an ideal full-wave rectifier bridge and a PMMC instrument. A DC current of 1 mA produces a full-scale deflection of the instrument. The resistance of the instrument is 100 Ω. A voltage of 100 V (rms) is applied to the input terminals. The value of R required is?
a) 63.56 Ω
b) 89.83 Ω
c) 89.83 kΩ
d) 141.3 kΩ

12. In the circuit given below, the value of ZL for maximum power to be transferred is _____________

a) R
b) R + jωL
c) R – jωL
d) jωL

13. A current I given by I = – 8 + 62–√ (sin (ωt + 30°)) A is passed through three meters. The respective readings (in ampere) will be?
a) 8, 6 and 10
b) 8, 6 and 8
c) – 8, 10 and 10
d) -8, 2 and 2

14. The discharge of a capacitor through a ballistic galvanometer produces a damped frequency of 0.125 Hz and successive swings of 120, 96 and 76.8 mm. The logarithmic decrement is?
a) 0.225
b) 0.565
c) 0.484
d) 0.7887

15. 12, 1 H inductors are used as edge to form a cube. The inductance between two diagonally opposite corners of the cube is ____________
a) 56 H
b) 106 H
c) 2 H
d) 32 H