MCQOPTIONS
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MCQOPTIONS
This section includes 188 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
The purpose of a parallel circuit resonance is to magnify |
| A. | Current |
| B. | Voltage |
| C. | Power |
| D. | Frequency |
| Answer» C. Power | |
| 52. |
Two waves of the same frequency have opposite phase when the phase angle between them is |
| A. | 360° |
| B. | 180° |
| C. | 90° |
| D. | 0° |
| Answer» C. 90° | |
| 53. |
Inductance of a coil Varies |
| A. | Directly as the cross-sectional area of magnetic core |
| B. | Directly as square of number of turns |
| C. | Inversely as the length of the iron path |
| D. | As A to C |
| Answer» E. | |
| 54. |
Magnitude of current at resonance in R-L-C circuit |
| A. | Depends upon the magnitude of R |
| B. | Depends upon the magnitude of L |
| C. | Depends upon the magnitude of C |
| D. | Depends upon the magnitude of R, Land C |
| Answer» B. Depends upon the magnitude of L | |
| 55. |
Time constant of a circuit is the time in seconds taken after the application of voltage to each |
| A. | 25% of maximum value |
| B. | 50% of maximum value |
| C. | 63% of maximum value |
| D. | 90% of the maximum value |
| Answer» D. 90% of the maximum value | |
| 56. |
Pure inductive circuit takes power from the A.C. line when |
| A. | Applied voltage decreases but current increases |
| B. | Applied voltage increases but current decreases |
| C. | Both applied voltage and current increase |
| D. | Both applied voltage and current decrease |
| Answer» B. Applied voltage increases but current decreases | |
| 57. |
In a purely inductive circuit |
| A. | Actual power is zero |
| B. | Reactive power is zero |
| C. | Apparent power is zero |
| D. | None of above is zero |
| Answer» B. Reactive power is zero | |
| 58. |
Which of the following waves has the highest value of peak factor ? |
| A. | Square wave |
| B. | Sine wave |
| C. | Half wave rectified sine wave |
| D. | Triangular wave |
| Answer» D. Triangular wave | |
| 59. |
The product of apparent power and cosine of the phase angle between circuit voltage and current is |
| A. | True power |
| B. | Reactive power |
| C. | Volt-amperes |
| D. | Instantaneous power |
| Answer» B. Reactive power | |
| 60. |
A parallel AC. circuit in resonance will |
| A. | Have a high voltage developed across each inductive and capacitive section |
| B. | Have a high impedance |
| C. | Act like a resistor of low value |
| D. | Have current in each section equal to the line current |
| Answer» C. Act like a resistor of low value | |
| 61. |
The voltage of domestic supply is 220 V. This figure represents |
| A. | Mean value |
| B. | r.m.s. value |
| C. | Peak value |
| D. | Average value |
| Answer» C. Peak value | |
| 62. |
Power factor of the following circuit will be unity |
| A. | Inductance |
| B. | Capacitance |
| C. | Resistance |
| D. | Both A and B |
| Answer» D. Both A and B | |
| 63. |
Power factor of an inductive circuit is usually improved by connecting capacitor to it in |
| A. | Parallel |
| B. | Series |
| C. | Either A or B |
| D. | None of the above |
| Answer» B. Series | |
| 64. |
The effective resistance of an iron-cored choke working on ordinary supply frequency is more than its true resistance because of |
| A. | Iron loss in core |
| B. | Skin effect |
| C. | Increase in temperature |
| D. | Capacitive effect between adjacent coil turns |
| Answer» B. Skin effect | |
| 65. |
What will be the phase angle between two alternating waves of equal frequency, when one wave attains maximum value the other is at zero value? |
| A. | 0° |
| B. | 45° |
| C. | 90° |
| D. | 180° |
| Answer» D. 180° | |
| 66. |
For the same peak value which of the following wave will 'have the highest r.m.s. value? |
| A. | Square wave |
| B. | Half wave rectified sine wave |
| C. | Triangular wave |
| D. | Sine wave |
| Answer» B. Half wave rectified sine wave | |
| 67. |
In a sine wave the slope is constant |
| A. | Between 0° and 90° |
| B. | Between 90° and 180° |
| C. | Between 180° and 270° |
| D. | No where |
| Answer» E. | |
| 68. |
For the same peak value, which of the following wave has the least mean value? |
| A. | Half wave rectified sine wave |
| B. | Triangular wave |
| C. | Sine wave |
| D. | Square wave |
| Answer» B. Triangular wave | |
| 69. |
The square waveform of current has following relation between r.m.s. value and average value. |
| A. | r.m.s. value is equal to average value |
| B. | r.m.s. value of current is greater than average value |
| C. | r.m.s. value of current is less than average value |
| D. | None of the above |
| Answer» B. r.m.s. value of current is greater than average value | |
| 70. |
The time constant of the capacitance circuit is defined as the time during which voltage |
| A. | Falls to 36.8% of its final steady value |
| B. | Rises to 38.6% of its final steady value |
| C. | Rises to 63.2% of its final steady value |
| D. | None of the above |
| Answer» D. None of the above | |
| 71. |
The period of a sine wave is ___________ seconds. Its frequency is |
| A. | 20 Hz |
| B. | 30 Hz |
| C. | 40 Hz |
| D. | 50 Hz |
| Answer» E. | |
| 72. |
If two sinusoids of the same frequency but of different amplitudes and phase angles are subtracted, the resultant is |
| A. | A sinusoid of the same frequency |
| B. | A sinusoid of half the original frequency |
| C. | A sinusoid of double the frequency |
| D. | Not a sinusoid |
| Answer» B. A sinusoid of half the original frequency | |
| 73. |
In an AC. circuit, a low value of kVAR compared with kW indicates |
| A. | Low efficiency |
| B. | High power factor |
| C. | Unity power factor |
| D. | Maximum load current |
| Answer» C. Unity power factor | |
| 74. |
The r.m.s. value of half wave rectified sine wave is 200 V. The r.m.s. value of full wave rectified AC. will be |
| A. | 282.8 V |
| B. | 141.4 V |
| C. | 111 V |
| D. | 100 V |
| Answer» B. 141.4 V | |
| 75. |
The phosphors for which of the following pair are 180° out of phase for VL, VC and VR? |
| A. | VC and VR |
| B. | VL and VR |
| C. | VC and VL |
| D. | None of the above |
| Answer» D. None of the above | |
| 76. |
Power factor of an electrical circuit is equal to |
| A. | R/Z |
| B. | Cosine of phase angle difference between current and voltage |
| C. | Ratio of useful current to total current Iw/I |
| D. | All above |
| Answer» E. | |
| 77. |
The inductance of a coil can be increased by |
| A. | Increasing core length |
| B. | Decreasing the number of turns |
| C. | Decreasing the diameter of the former |
| D. | Choosing core material having high relative permeability |
| Answer» E. | |
| 78. |
The transient currents are associated with the |
| A. | Changes in the stored energy in the inductors and capacitors |
| B. | Impedance of the circuit |
| C. | Applied voltage to the circuit |
| D. | Resistance of the circuit |
| Answer» B. Impedance of the circuit | |
| 79. |
In any A.C. circuit always |
| A. | Apparent power is more than actual power |
| B. | Reactive power is more than apparent power |
| C. | Actual power is more than reactive power |
| D. | Reactive power is more than actual power |
| Answer» B. Reactive power is more than apparent power | |
| 80. |
The input of an A.C. circuit having power factor of 0.8 lagging is 40 kVAThe power drawn by the circuit is%! |
| A. | 12 kW |
| B. | 22 kW |
| C. | 32 kW |
| D. | 64 kW |
| Answer» D. 64 kW | |
| 81. |
In an A.C. circuit power is dissipated in%! |
| A. | Resistance only |
| B. | Inductance only |
| C. | Capacitance only |
| D. | None of the above |
| Answer» B. Inductance only | |
| 82. |
At very low frequencies a series R-C circuit behaves as almost purely%! |
| A. | Resistive |
| B. | Inductive |
| C. | Capacitive |
| D. | None of the above |
| Answer» D. None of the above | |
| 83. |
The series and parallel resonance on L-C circuit' differs in that%! |
| A. | Series resistance needs a low-resistance source for sharp rise in current |
| B. | Series resonance needs a high-resistance source for sharp increase in current |
| C. | Parallel resonance needs a low-resistance source for a sharp increase in impedance |
| D. | Parallel resonance needs a low-resistance source for a sharp rise in line current |
| Answer» B. Series resonance needs a high-resistance source for sharp increase in current | |
| 84. |
Power factor of an electrical circuit is equal to%! |
| A. | R/Z |
| B. | Cosine of phase angle difference between current and voltage |
| C. | Ratio of useful current to total current Iw/I |
| D. | All above |
| Answer» E. | |
| 85. |
*$_In a highly capacitive circuit the? |
| A. | Apparent power is equal to the actual power |
| B. | Reactive power is more than the apparent power |
| C. | Reactive power is more than the actual power |
| D. | Actual power is more than its reactive power |
| Answer» D. Actual power is more than its reactive power | |
| 86. |
*$_Two waves of the same frequency have opposite phase when the phase angle between them is? |
| A. | 360° |
| B. | 180° |
| C. | 90° |
| D. | 0° |
| Answer» C. 90¬¨‚àû | |
| 87. |
*$_Which of the following statements pertains to resistors only?? |
| A. | Can dissipate considerable amount of power |
| B. | Can act as energy storage devices |
| C. | Connecting them in parallel increases the total value |
| D. | Oppose sudden changes in voltage |
| Answer» B. Can act as energy storage devices | |
| 88. |
*$_Pure inductive circuit? |
| A. | Consumes some power on average |
| B. | Does not take power at all from a line |
| C. | Takes power from the line during some part of the cycle and then returns back to it during other part of the cycle |
| D. | None of the above |
| Answer» D. None of the above | |
| 89. |
*$_Wire-wound resistors are unsuitable for use at high frequencies because they? |
| A. | Create more electrical noise |
| B. | Are likely to melt under excessive eddy current heat |
| C. | Consume more power |
| D. | Exhibit unwanted inductive and capacitive effects |
| Answer» E. | |
| 90. |
*$_The frequency of an alternating current is? |
| A. | The speed with which the alternator runs |
| B. | The number of cycles generated in one minute |
| C. | The number of waves passing through a point in one second |
| D. | The number of electrons passing through a point in one second |
| Answer» D. The number of electrons passing through a point in one second | |
| 91. |
*/*_Power factor of an electrical circuit is equal to? |
| A. | R/Z |
| B. | Cosine of phase angle difference between current and voltage |
| C. | Ratio of useful current to total current Iw/I |
| D. | All above |
| Answer» E. | |
| 92. |
*/*_Pure inductive circuit takes power from the A.C. line when? |
| A. | Applied voltage decreases but current increases |
| B. | Applied voltage increases but current decreases |
| C. | Both applied voltage and current increase |
| D. | Both applied voltage and current decrease |
| Answer» B. Applied voltage increases but current decreases | |
| 93. |
*/*_A sine wave has a frequency of 50 Hz. Its angular frequency is __________ radian/second.? |
| A. | 100 n |
| B. | 50 jt |
| C. | 25 JT |
| D. | 5 n |
| Answer» B. 50 jt | |
| 94. |
*/*_A parallel AC. circuit in resonance will? |
| A. | Have a high voltage developed across each inductive and capacitive section |
| B. | Have a high impedance |
| C. | Act like a resistor of low value |
| D. | Have current in each section equal to the line current |
| Answer» C. Act like a resistor of low value | |
| 95. |
*/*_For the same peak value which of the following wave will 'have the highest r.m.s. value?? |
| A. | Square wave |
| B. | Half wave rectified sine wave |
| C. | Triangular wave |
| D. | Sine wave |
| Answer» B. Half wave rectified sine wave | |
| 96. |
*/*_Power factor of an inductive circuit is usually improved by connecting capacitor to it in? |
| A. | Parallel |
| B. | Series |
| C. | Either A or B |
| D. | None of the above |
| Answer» B. Series | |
| 97. |
*/*_If two sinusoids of the same frequency but of different amplitudes and phase angles are subtracted, the resultant is? |
| A. | A sinusoid of the same frequency |
| B. | A sinusoid of half the original frequency |
| C. | A sinusoid of double the frequency |
| D. | Not a sinusoid |
| Answer» B. A sinusoid of half the original frequency | |
| 98. |
*/*_The square waveform of current has following relation between r.m.s. value and average value.? |
| A. | r.m.s. value is equal to average value |
| B. | r.m.s. value of current is greater than average value |
| C. | r.m.s. value of current is less than average value |
| D. | None of the above |
| Answer» B. r.m.s. value of current is greater than average value | |
| 99. |
*/*_Capacitive susceptance is a measure of? |
| A. | Reactive power in a circuit |
| B. | The extent of neutralization of reactive power in a circuit |
| C. | A purely capacitive circuit's ability to pass current |
| D. | A purely capacitive circuit's ability to resist the flow of current |
| Answer» D. A purely capacitive circuit's ability to resist the flow of current | |
| 100. |
*/*_Capacitive reactance is more when? |
| A. | Capacitance is less and frequency of supply is less |
| B. | Capacitance is less and frequency of supply is more |
| C. | Capacitance is more and frequency of supply is less |
| D. | Capacitance is more and frequency of supply is more |
| Answer» B. Capacitance is less and frequency of supply is more | |