# Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-2

16. A passive network

a) Has no current source
b) Has no e.m.f. source
c) Has neither of the above
d) Has either of the above

Ans: (b)

17.If an electrical network having one or more than one voltage sources is transformed into equivalent electrical network with a single voltage source (which is open circuit voltage of previous circuit) with series internal resistance of the network with all voltage sources replaced by their internal resistances.

The above illustration is called

a) Reciprocity theorem
b) Thevenin’s theorem
c) Superposition theorem
d) Duality

Ans: (b)

18. In the circuit given below, the ammeter reads 0.1 ampere and voltmeter 10 volts. The internal resistance of the ammeter is 1 ohm and that of voltmeter is 500 ohms. What is the value of R?

a) 110 ohms
b) 120 ohms
c) 115 ohms
d) 112.5 ohms
e) 125 ohms

Ans: (e)

19.In the circuit given below the power factor will be

a) Lagging
c) Zero
d) Unity,

Ans: (b)

20. If a = 4 < 20° and b = 2 < 10° then the value of a/b, will be :

a) 2 < 10°
b) 2 < 30°
c) 2 < -10°
d) 2 < 20°

Ans: (a)

21. The conjugate of the complex quantity (a + jb) will be

a) – a – jb
b) – a + jb
c) A - jb
d) Ja – b

Ans: (c)

22. Mass in the MKS unit system is analogous to

a) Resistance
b) Voltage
c) Inductance
d) Capacitance

Ans: (d)

23.A damped oscillation has the equation I = 50 e-10tsin 628 t. What will be the frequency of a oscillation?

a) 50 Hz
b) 75 Hz
c) 100 Hz
d) 60 Hz

Ans: (c)

24. In a loss-free R-L-C circuit the transient current is

a) Sinusoidal
b) Oscillating
c) None-oscillating
d) Square wave

Ans: (a)

25. A 0.5 meter long conductor carrying a current of 2 amperes is placed in a magnetic field having the flux density of 0.05 wb/m2. What will be the amount of force experienced by the conductor?

a) 1 New
b) 2 New
c) 0.05 New
d) 0.5 New

Ans: (c)

26. Two parallel conductors carry the same current in the same direction. What kind of mutual force they will experience?

a) Repulsion
b) Attraction
c) Zero
d) Either (a) or (b)

Ans: (b)

27. Which of the following statement is correct?

a) The flow of current in the electric circuit involves discontinuous expenditure of energy.
b) The flow of current in the electric circuit requires energy for creating the current but not to maintain it.
c) In the magnetic circuit energy is needed continuously to maintain the flux.
d) In the magnetic circuit energy is needed for creating the flux initially but not to maintain it.

Ans: (c)

28. If a coil has a resistance of 10 ohms and an inductance of 1 H, what will be the value of current 0.1 second after switching on a 500 V d.c. supply?

a) 6.32 A
b) 3.16 A
c) 3.7 A
d) 4.0 A

Ans: (b)

29. The r.m.s. value of an alternating current is given by steady (d.c) current which when flowing through a given circuit for given time produces

a) The same heat as produced by a.c. when flowing through the same circuit
b) The less heat than produced by a.c. when flowing through the same circuit
c) The more heat than produced by a.c. when flowing through the same circuit
d) 14.4 calories

Ans: (a)

30.In case of an unsymmetrical alternating current the average value must always be taken over

a) The half cycle
b) The whole cycle
c) Unsymmetrical part of the waveform
d) The quarter cycle

Ans: (b)