Electrical Basic Questions 15

Electrical Basic Questions 15

41. What is the half-power bandwidth of a parallel resonant circuit which has a resonant frequency of 3.6 MHz and Q of 218?

A. 16.5 kHz
B. 1.65 kHz
C. 16.5 MHz
D. 165 kHz

ANS : A

42. Which one of the following elements serves as a protection against overload?

A. Fuse
B. Switch
C. Resistor
D. Relay

ANS: D

43. Transient period is considered over after

A. 5 TAA
B. N1 Taa
C. 100 Taa
D. 6 Taa

ANS : A

44. What rating of a resistor determines its ability to absorb heat?

A. Wattage
B. Ohmic
C. Current
D. Voltage

ANS : A

45. An open inductor has:
A. Zero resistance and infinite inductance
B. Infinite resistance and infinite inductance
C. Infinite resistance and zero inductance
D. Zero resistance and zero inductance

ANS: C

Electrical Basic Questions 15

46.What is the reading of an ohmmeter for a shorted capacitor?

A. Mho

B. ZerO
C. Infinity
D. k Ohm
E. M Ohm

ANS : B

47. What capacitance exists not through design but simply because two conducting surfaces are relatively close to each other?

A. MSurge
B.Stray
C. Natural
D. Normal

ANS : B

48. The average value of a triangular or sawtooth wave is_______ times its peak value.

A. 0.577
B. 0.500
C. 0.318
D. 0.637

ANS :B

49.A series RLC circuit consists of a 10 Ohm 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.

A. 40uH
B. 40 mH
C. 40 pH
D. 40 nH

ANS : A

50. What is the peak factor of a triangular wave?
A. 1.16
B. 1.73
C. 1.41
D. 1.11

ANS : B

Electrical Basic Questions 15

51. Effects of capacitance:

A. It opposes any change in the amount of voltage
B. Voltage is lagged behind the current by a quarter cycle
C. Electric energy is stored in the capacitor in the form of electrostatic field
D. All of the above

ANS : D

52. Points to be considered in choosing a capacitor

A. Working voltage
B. Type of dielectric
C. Capacitance
D. All of the above

ANS 😀

53. Permeability is otherwise known as

A. Magnetic conductivity
B. Magnetic susceptibility
C. Electric conductivity
D. Electric susceptibility

ANS : A

54. The impedance in the study of electronics is represented by resistance and

A. Reactance
B. Inductance
C. Capacitance
D. Inductance and capacitance

ANS : A

55. Loop currents should be assumed to flow in which direction

A. Straight
B. Clockwise
C. Counter-clockwise
D. Either B or C arbitrarily

ANS 😀

Electrical Basic Questions 15

56. What determines the direction of induced emf in a conductor or coil?

A. Corkscrew rule
B. Fleming’s left hand rule
C. Fleming’s right hand rule
D. Ampere’s circuital law

ANS : C

57. The reason why electrical appliances are connected in parallel.

A. It is a simple circuit
B. This makes the operation of appliances independent of each other
C. This results in reduced power consumption
D. All of the above

ANS : B

58. Which of the following does not affect resistance?

A. Mass
B. Resistivity
C. Cross-sectional area
D. Length

ANS : A

59. Which of the following is not considered a physical factor affecting resistance?

A. Temperature
B.Length
C.Material type
D.Cross-sectional

ANS :A

Electrical Basic Questions 15

60. 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?

A. 1.5
B. 1.25
C. 2.5
D. 0.5

ANS : B

Electrical Basic Questions 15

61. A trigger circuit consisting of a capacitor of 0.01 µF is connected in series with a resistor. If the circuit requires 100 Vdc to operate, determine the value of the resistor when time constant is 0.009s.

A. 900 Ohm
B. 900 MOhm
C. 900 KOhm
D. 900 GOhm

ANS : C

62. The graph between an alternating quantity and time is called

A.Sine wave
B. Curve
C. Waveform
D. A plot

ANS :C

Electrical Basic Questions 15

63. Which of the following is the most popular waveform?

A. Sinusoidal
B. Square wave
C. Triangular
D. Sawtooth

ANS : A

64. Which of the following does not refer to electrical energy?

A. Joule
B. Volt-Ampere
C. Watt-second
D. Volt-coulomb

ANS : B

65. What is the resonant frequency of a circuit when L of 25 micro henrys and C of 10 pico farads are in parallel?

A. 10.1 kHz
B. 10.1 MHz
C.101 MHz
D. 101 kHz

ANS : B

Electrical Basic Questions 15

66. And ideal current source has an internal conductance of_______ Siemen(s)

A. Infinite
B. Zero
C. One
D. One million

ANS : B

67. A capacitance of 6 µµF means

A. 6 pF
B.6 nF
C.6 uF
D.6 aF

ANS : A

68. The voltage cannot be exactly in phase with the current in a circuit that contains:

A. Only Capacitance
B. Only resistance
C. Inductance and capacitance
D. Inductance, capacitance and resistance

ANS : A

Electrical Basic Questions 15

69. The charge in the capacitor is stored at the:

A. Terminals
B. Plates
C. Dielectric
D. Air

ANS : B

70. The reactance curve is a plot of frequency versus_________ for a series RLC circuit

A. Voltage
B. Current
C. Gain
D. Impedance

ANS : B

Electrical Basic Questions 15

71. For a series circuit, the higher the quality factor

A. The greater the bandwidth
B. The narrower the passband
C. The broader the resonance curve
D. The wider the pass band

ANS : B

72. “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

A. Compensation theorem
B. Reciprocity theorem
C. Millman’s theorem
D. Superposition theorem

ANS : A

73. The internal resistance of an ideal current source is

A. Infinite
B. Zero
C. Equal to the load resistance
D. To be determined

ANS : A

Electrical Basic Questions 15

74. If three 100-pF capacitors are connected in series, then the total capacitance is

A. 300 pF
B. 100 pF
C. 50 pF
D. 33.3 pF

ANS : D

75. An inductance of 1 mH is

A. 0.001 H
B. 0.01 H
C. 0.0001 H
D. 0.10 H

76. A capacitor is basically constructed of

A. Two conductors separated by a dielectric
B. Two dielectric separated by a conductor
C. Conductors and dielectric
D. Conductors and semiconductors

ANS : A

77. In an inductive coil, the rate of rise of current is maximum

A. Near the final maximum value of current
B. At mid-value of current
C. At half-power points
D. After one time constant

ANS : A

Electrical Basic Questions 15

78. Two complex numbers or phasors are said to be conjugate if they

A. Differ only in the algebraic sign of their quadratic components
B. Differ only in the algebraic sign of their real components
C. Are equal in their real and quadrature components including algebraic signs
D. Are equal in their real components but differ in their quadrature components including algebraic signs.

ANS : A

79. In an ac circuit with a resistive branch and an inductive branch in parallel, the

A Voltage across the inductance leads the voltage across the resistance by 90°
B. Resistive branch current is 90° out of phase with the inductive branch current
C. Resistive and inductive branch currents have the same phase
D. Resistive and inductive branch currents are 180° out-of-phase

ANS : B

Electrical Basic Questions 15

80. In an ac circuit with XL and R in series, the

A. Voltages across R and XL are in phase
B. Voltage across R lags the voltage across XL by 90°
C. Voltages across R and XL are 180° out-of-phase
D. Voltage across R leads the voltage across XL by 90°

ANS : B

81. Leakage resistance in a capacitor results into

A. Internal heating
B. Internal bleeding
C. Shorter useful life
D. Short-circuiting

ANS : A

82. Voltage resonance means

A. Series resonance
B. Parallel resonance
C. Current magnification
D. Gain magnification

ANS : A

83. The unit of elastance is

A. Farad
B. Daraf
C. Siemen
D. Henry

ANS : B

84. The farad is not equivalent to which of the following combination of units

A. CV­2
B. C2/J
C. C/V
D. J/V2

ANS : A

Electrical Basic Questions 15

85. Which component opposes voltage change?

A. Resistor
B. Inductor
C. Capacitor
D. Transistor

ANS : C

86. What is the peak factor for alternating current or voltage varying sinusiodally?

A. 1.4142
B. 0.707
C. 0.636
D. 1.11

ANS : A

87. Which of the following is not a factor affecting dielectric strength?

A. Mass
B. Moisture content
C. Temperature
D. Thickness

ANS : A

88. The superposition theorem is used when the circuit contains

A. Reactive elements
B. Active elements
C. Number of voltage sources
D. Single voltage source

ANS : C

89. What refers to such work at very low temperatures, near absolute zero?

A. Cryogenics
B. Superconductivity
C. Subsonic
D. Thermionic

ANS : A

Electrical Basic Questions 15

90. A factor that states how much the resistance changes for a change in temperature?

A. Resistivity
B. Specific resistance
C. Coefficient of temperature change
D. Temperature coefficient of resistance

ANS : D

91. An alloy composed of 84 % copper, 12 % manganese and 4 % nickel.

A. Manganin
B. Constantan
C. Nichrome
D. German silver wire

ANS : A

92. A law which states that when a constant electromotive force is applied to a circuit consisting of a resistor and capacitor connected in series, the time taken for the potential on the plates of the capacitor to rise to any given fraction of its final value depends only on the product of capacitance and resistance.

A. Child’s law
B. CR law
C. Coulomb’s law
D. Debye T3 law

ANS : B

93. At parallel resonance, the currents flowing through L and C are

A. Infinite
B. Zero
C. Unequal
D. Equal

ANS : D

94. In a rectangular wave, the peak factor is

A. 1.16
B. 1.73
C. 1.11
D. 1.0

ANS : D

Electrical Basic Questions 15

95. In an RL series circuit,

A. Current lags voltage by less than 90˚
B. Current lags voltage by 180˚
C. Current lags voltage by 90˚
D. Current leads voltage by 90˚

ANS : A

96. In a pure capacitance,

A. Current leads voltage by 90˚
B. Current leads voltage by 180˚
C. Current lags voltage by 90˚
D. Current lags voltage by 180˚

ANS : A

97. The ohmic value of a resistor with negative temperature coefficient

A. Increases with increasing temperature
B. Increase with decreasing temperature
C. Stays unchanged with temperature change
D. Stays unaffected even with increasing temperature

ANS : B

98. Which of the statements below is not true?

A. Current source is an active element
B. Resistor is a linear element
C. Voltage source is a passive element
D. Diode is a non-linear element

ANS : C

99. Which of the following elements is active?

A. Resistor
B. Inductor
C. Capacitor
D. Ideal voltage source

ANS : D

100. What is the complex impedance of a circuit with an absolute resistance of 300 Ω?

A. 0 + j 300 Ω
B. 300 + j 90 Ω
C. 0 – j 300 Ω
D. 300 + j 0 Ω

ANS : D

Electrical Basic Questions 15