ELECTRICAL CIRCUITS Multiple Choice Questions Part 4.

1 In a series RLC circuit
Increasing the frequency decreases the resistance
Increasing the frequency increases the resistance
Both XL and XC change as frequency changes
Impedance will always decrease

2 The average value of a triangular or sawtooth wave is times its peak value.
⦁     0.577
⦁    0.500
⦁    0.318
⦁    0.637

3 A series RLC circuit consists of a 10 fi resistor in series with L = 10 µH, and C = 100 µF. Determine a new value of I, for which the resonant frequency is one –half the original value.
40 µH
40 mH
40 pH
40 nH

4 The impedance in the study of electronics is represented by resistance and
Inductance
Capacitance
Inductance and capacitance
Reactance

5 Loop currents should be assumed to flow in which direction
Straight
Clockwise
Counter-clockwise
Either B or C arbitrarily selected

6 What determines the direction of induced emf in a conductor or coil?
Cork screw rule
Fleming’s left hand rule
Ampere’s circuital law
Fleming’s right hand rule

7 The superposition theorem is used when the circuit contains
Reactive elements
Active elements
Number of voltage sources
Single voltage source

8 What refers to such work at very low temperatures, near absolute zero?
Cryogenics
Superconductivity
Subsonic
Thermionic

9 Which of the statements below is not true?
Current source is an active element
Resistor is a linear element
Voltage source is a passive element
Diode is a non-linear element

10 The potential gradient in a cable is maximum in
Conductor
Outer sheath
Insulation
Uniformly all over

11 Which statement is true about a passive circuit?
A circuit with neither a source of current nor a source of potential difference
A circuit with a voltage source
A circuit with a current source
A circuit with only resistance as a load

12 What is the conductance of a circuit having three 10 fi resistors in parallel?
0.3 S
⦁      3.33 S
⦁      0.33 S
⦁      30 S

13 If an emf in circuit A produces a current in circuit B, then the same emf in circuit
B produces the same current in circuit A. this theorem is known as
Maximum power transfer theorem
Millman’s theorem
Reciprocity theorem
Norton’s theorem

14 According to Gauss theorem, flux can be equated to
Charge
Field intensity
Current
Voltage

15 An open resistor when checked with an ohmmeter reads
Zero
Infinite
High but within the tolerance
Low but not zero

16 For parallel capacitors, total charge is
The sum of individual charges
Equal to the charge of either capacitors
Equal to the product of the charges
The quotient of the charges

17 In a complex resistance-reactance plane, XL is represented
By an axis opposite the R axis
By an axis perpendicular to the XC axis
By an axis opposite the XC axis
By an axis parallel to the R axis

18 When the net reactance in a series coil-capacitor circuit is zero at frequency f, the nature of its reactance of frequency 2f is
Inductive
Capacitive
Resistive
Infinite

19 Refers specifically to steady state values of quantities in ac circuits which are
complex numbers.
Domain
Scalar quantity
Vector quantity
Phasor quantity

20 A capacitor is used to
Block dc current
Pass dc current
Open voltage source
Short the voltage source

21 The usual load of a dc circuit is a/an
Resistor
Capacitor
Inductor
Both inductor and capacitor

22 What is the value of a carbon composition resistor with the following color code:
Brown, white, orange, red.
190 fi; 10 %
⦁      19 kfi; 2 %
⦁      19 kfi; 20 %
⦁      1.9 kfi; 2 %

23 How many coulombs are delivered by a storage battery in 25 hours if it is supplying current at the rate of 3 A?
⦁      2.592 x 105 C
⦁      2.592 x 103 C
⦁      2.592 x 108 C
⦁      2.592 x 1012 C

24 The temperature-resistance coefficient of pure gold is
A.     0.0034
B.     0.0037
C.     0.0038
D.     0.0039

25 The capacitor opposes any change in voltage across it by
Passing a voltage proportional to the rate of change of current
Acting as a short circuit at time equal to zero
Passing a current proportional to the rate of change of voltage
Acting as a short circuit at time equal to infinity

26 What is the most common non-sinusoidal waveform?
Square wave
Triangular wave
Trapezoidal wave
Sawtooth wave

27 What is the peak factor of a triangular wave?
⦁      1.16
⦁      1.73
⦁      1.41
⦁      1.11

28 Effects of capacitance
It opposes any change in the amount of voltage
Voltage is lagged behind the current by a quarter cycle
Electric energy is stored in the capacitor in the form of electrostatic field
All of the above

29 The reason why electrical appliances are connected in parallel.
It is a simple circuit
This makes the operation of appliances independent with each other
This results in reduced power consumption
All of the above

30 A capacitor is basically constructed of
Two conductors separated by a dielectric
Two dielectric separated by a conductor
Conductors and dielectric
Conductors and semiconductors

31 In an inductive coil, the rate of rise of current is maximum
Near the final maximum value of current
At mid-value of current
At half-power points
After one time constant

32 Two complex numbers or phasors are said to be conjugate if they
Differ only in the algebraic sign of their quadratic components
Differ only in the algebraic sign of their real components
Are equal in their real and quadrature components including algebraic signs
Are equal in their real components but differ in their quadrature components including algebraic signs.

33 Which of the following dielectric materials makes the highest-capacitance
capacitor?
Air
Barium-strontium titanite
Mica
Electrolyte

34 In a circuit, an active element is one which
Supplies energy
Amplifies signal

35 The of an alternating quantity is defined as the fractional part of a period or
cycle through which the quantity has advanced from selected origin.
Phase
Frequency
Amplitude
Waveform

36 An inductive circuit of resistance 16.5 fi and inductance of 0.14 H takes a current
of 25 A. if the frequency is 50 Hz, find the supply voltage.
⦁     1501 V
⦁     1174 V
⦁     1877 V
⦁      991 V

37 What is the total effective capacitance of two 0.25 µF capacitors connected in series?
⦁      0.125 µF
1.25 µF
0.50 µF
2.5 if

38 What can be used to estimate resonant frequency and to find reactance at any frequency for any value of capacitor or inductor?
Smith chart
Reactance chart
Impedance chart
Resonance chart

39 For a parallel AC circuit, is used as a reference phasor.
Voltage
Power
Current
Resistance

40 A 0.09 microfarad capacitor is charged to 220 volts. How long in milliseconds will it discharged resistor has a resistance of 20,000 ohms?
⦁      1.5
⦁      2.5
⦁      1.25
⦁      0.5

41 “Any resistance R in a branch of a network in which a current I is flowing can be  replaced by a voltage equal to IR”. This states
Compensation theorem
Reciprocity theorem
Millman’s theorem
Superposition theorem

42 The internal resistance of an ideal current source is
Infinite
Zero
To be determined

43 Series resonant circuit is sometimes known as
Rejector circuit
Acceptor circuit
Inductive circuit
Capacitive circuit

44 Parallel resonant circuit is sometimes called as
Acceptor circuit
Rejector circuit
Inductive circuit
Capacitive circuit

45 When two pure sine waves of the same frequency and the same amplitude which are exactly 180˚ out-of-phase are added together, the result is
A wave with twice the amplitude
A wave with half the amplitude
Zero signal
A wave with twice the frequency

46 If two complex conjugates are added, components results.
In-phase
Complex
Out-of-phase

47 Norton’s theorem is Thevenin’s theorem.
The same as
The converse of
Older that
More accurate than

48 The  admittance  of  a  parallel  RLC  circuit   is   found   to   be  the sum of conductance and susceptances.
Algebraic
Arithmetic
Vector
Phasor

49 Which of the following has a positive temperature coefficient?
Mica
Manganin
Silicon
Carbon

50 The ratio of the flux density to the electric field intensity in the dielectric is called
Permittivity
Field intensity
Permeability
Elasticity