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.
| 101. |
*/*_Form Factor is the ratio of? |
| A. | Average value/r.m.s. value |
| B. | Average value/peak value |
| C. | r.m.s. value/average value |
| D. | r.m.s. value/peak value |
| Answer» D. r.m.s. value/peak value | |
| 102. |
*/*_The power factor of a D.C. circuit is always? |
| A. | Less than unity |
| B. | Unity |
| C. | Greater than unity |
| D. | Zero |
| Answer» C. Greater than unity | |
| 103. |
*/*_The period of a wave is? |
| A. | The same as frequency |
| B. | Time required to complete one cycle |
| C. | Expressed in amperes |
| D. | None of the above |
| Answer» C. Expressed in amperes | |
| 104. |
*/*_The ratio of active power to apparent power is known as factor.? |
| A. | Demand |
| B. | Load |
| C. | Power |
| D. | Form |
| Answer» D. Form | |
| 105. |
*/*_For a frequency of 200 Hz, the time period will be? |
| A. | 0.05 s |
| B. | 0.005 s |
| C. | 0.0005 s |
| D. | 0.5 s |
| Answer» C. 0.0005 s | |
| 106. |
*/*_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. | |
| 107. |
_ The safest value of current the human body can carry for more than 3 second is$? |
| A. | 4 mA |
| B. | 9 mA |
| C. | 15 mA |
| D. | 25 mA |
| Answer» C. 15 mA | |
| 108. |
_ Inductance of a coil Varies$? |
| 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. | |
| 109. |
_ The power consumed in a circuit element will be least when the phase difference between the current and voltage is$? |
| A. | 180° |
| B. | 90° |
| C. | 60° |
| D. | 0° |
| Answer» C. 60¬¨‚àû | |
| 110. |
_ The frequency of domestic power supply in India is$? |
| A. | 200 Hz |
| B. | 100 Hz |
| C. | 60 Hz |
| D. | 50 Hz |
| Answer» E. | |
| 111. |
_ In a loss-free R-L-C circuit the transient current is$? |
| A. | Oscillating |
| B. | Square wave |
| C. | Sinusoidal |
| D. | Non-oscillating |
| Answer» D. Non-oscillating | |
| 112. |
_ All definitions of power factor of a series R-L-C circuit are correct except$? |
| A. | Ratio of net reactance and impedance |
| B. | Ratio of kW and kVA |
| C. | Ratio of J and Z |
| D. | Ratio of W and VA |
| Answer» B. Ratio of kW and kVA | |
| 113. |
_ The inductance of a coil can be increased by$? |
| A. | Increasing core length |
| B. | Decreasing the number of turns |
| C. | Decreasing the diameter of the former |
| D. | Choosing core material having high relative permeability |
| Answer» E. | |
| 114. |
_ In a purely inductive circuit$? |
| 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 | |
| 115. |
_ The voltage of domestic supply is 220 V. This figure represents$? |
| A. | Mean value |
| B. | r.m.s. value |
| C. | Peak value |
| D. | Average value |
| Answer» C. Peak value | |
| 116. |
_ In a sine wave the slope is constant$? |
| A. | Between 0° and 90° |
| B. | Between 90° and 180° |
| C. | Between 180° and 270° |
| D. | No where |
| Answer» E. | |
| 117. |
_ The effective resistance of an iron-cored choke working on ordinary supply frequency is more than its true resistance because of$? |
| A. | Iron loss in core |
| B. | Skin effect |
| C. | Increase in temperature |
| D. | Capacitive effect between adjacent coil turns |
| Answer» B. Skin effect | |
| 118. |
_ In an AC. circuit, a low value of kVAR compared with kW indicates$? |
| A. | Low efficiency |
| B. | High power factor |
| C. | Unity power factor |
| D. | Maximum load current |
| Answer» C. Unity power factor | |
| 119. |
_ The time constant of the capacitance circuit is defined as the time during which voltage$? |
| A. | Falls to 36.8% of its final steady value |
| B. | Rises to 38.6% of its final steady value |
| C. | Rises to 63.2% of its final steady value |
| D. | None of the above |
| Answer» D. None of the above | |
| 120. |
_ Time constant of an inductive circuit$? |
| A. | Increases with increase of inductance and decrease of resistance |
| B. | Increases with the increase of inductance and the increase of resistance |
| C. | Increases with the decrease of inductance and decrease of resistance |
| D. | Increases with decrease of inductance and increase of resistance |
| Answer» B. Increases with the increase of inductance and the increase of resistance | |
| 121. |
_ Time constant of a capacitive circuit$? |
| A. | Increases with the decrease of capacitance and decrease of resistance |
| B. | Increases with the decrease of capacitance and increase of resistance |
| C. | Increases with the increase of capacitance and decrease of resistance |
| D. | Increase with increase of capacitance and increase of resistance |
| Answer» E. | |
| 122. |
_ Power factor of the following circuit will be zero$? |
| A. | Resistance |
| B. | Inductance |
| C. | Capacitance |
| D. | Both B and C |
| Answer» E. | |
| 123. |
_ In AC. circuits, laminated iron is invariably used in order to$? |
| A. | Reduce eddy current loss |
| B. | Increase heat radiation |
| C. | Make assembly cheap and easier |
| D. | Reduce circuit permeability |
| Answer» B. Increase heat radiation | |
| 124. |
_ The power factor at resonance in R-L-C parallel circuit is$? |
| A. | Zero |
| B. | 0.08 lagging |
| C. | 0.8 leading |
| D. | Unity |
| Answer» E. | |
| 125. |
_ The r.m.s. value of alternating current is given by steady (D.C.) current which when flowing through a given circuit for a given time produces$? |
| A. | The more heat than produced by A.C. when flowing through the same circuit |
| B. | The same heat as produced by A.C. when flowing through the same circuit |
| C. | The less heat than produced by A.C. flowing through the same circuit |
| D. | None of the above |
| Answer» C. The less heat than produced by A.C. flowing through the same circuit | |
| 126. |
_ For a sine wave with peak value Imax the r.m.s. value is$? |
| A. | 0.5 Imax |
| B. | 0.707 |
| C. | 0.9 |
| D. | 1.414 Imax |
| Answer» C. 0.9 | |
| 127. |
_The purpose of a parallel circuit resonance is to magnify$? |
| A. | Current |
| B. | Voltage |
| C. | Power |
| D. | Frequency |
| Answer» C. Power | |
| 128. |
_Magnitude of current at resonance in R-L-C circuit$? |
| 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 | |
| 129. |
_Capacitors for power factor correction are rated in$? |
| A. | kW |
| B. | kVA |
| C. | kV |
| D. | kVAR |
| Answer» E. | |
| 130. |
_Form factor for a sine wave is$? |
| A. | 1.414 |
| B. | 0.707 |
| C. | 1.11 |
| D. | 0.637 |
| Answer» D. 0.637 | |
| 131. |
_If resistance is 20 Q. and inductance is 27 in a R-L series circuit, then time constant of this circuit will be$? |
| A. | 0.001 s |
| B. | 0.1 s |
| C. | 10 s |
| D. | 100 s |
| Answer» C. 10 s | |
| 132. |
_The best place to install a capacitor is$? |
| A. | Very near to inductive load |
| B. | Across the terminals of the inductive load |
| C. | Far away from the inductive load |
| D. | Any where |
| Answer» C. Far away from the inductive load | |
| 133. |
_The transient currents are associated with the$? |
| A. | Changes in the stored energy in the inductors and capacitors |
| B. | Impedance of the circuit |
| C. | Applied voltage to the circuit |
| D. | Resistance of the circuit |
| Answer» B. Impedance of the circuit | |
| 134. |
_Which of the following waves has the highest value of peak factor ?$? |
| A. | Square wave |
| B. | Sine wave |
| C. | Half wave rectified sine wave |
| D. | Triangular wave |
| Answer» D. Triangular wave | |
| 135. |
_In a pure inductive circuit if the supply frequency is reduced to 1/2, the current will$? |
| A. | Be reduced by half |
| B. | Be doubled |
| C. | Be four times as high |
| D. | Be reduced to one fourth |
| Answer» C. Be four times as high | |
| 136. |
Power factor of the following circuit will be unity$? |
| A. | Inductance |
| B. | Capacitance |
| C. | Resistance |
| D. | Both A and B |
| Answer» D. Both A and B | |
| 137. |
For the same peak value, which of the following wave has the least mean value?$? |
| A. | Half wave rectified sine wave |
| B. | Triangular wave |
| C. | Sine wave |
| D. | Square wave |
| Answer» B. Triangular wave | |
| 138. |
What will be the phase angle between two alternating waves of equal frequency, when one wave attains maximum value the other is at zero value?$? |
| A. | 0° |
| B. | 45° |
| C. | 90° |
| D. | 180° |
| Answer» D. 180¬¨‚àû | |
| 139. |
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$? |
| A. | 282.8 V |
| B. | 141.4 V |
| C. | 111 V |
| D. | 100 V |
| Answer» B. 141.4 V | |
| 140. |
The period of a sine wave is ___________ seconds. Its frequency is$? |
| A. | 20 Hz |
| B. | 30 Hz |
| C. | 40 Hz |
| D. | 50 Hz |
| Answer» E. | |
| 141. |
In the case of an unsymmetrical alternating current the average value must always be taken over$? |
| A. | Unsymmetrical part of the wave form |
| B. | The quarter cycle |
| C. | The half cycle |
| D. | The whole cycle |
| Answer» E. | |
| 142. |
A pure capacitor connected across an A.C. voltage consumed 50 W. This is due to$? |
| A. | The capacitive reactance in ohms |
| B. | The current flowing in capacitor |
| C. | The size of the capacitor being quite big |
| D. | The statement is incorrect |
| Answer» E. | |
| 143. |
In series resonant circuit, increasing inductance to its twice value and reducing capacitance to its half value$? |
| A. | Will change the maximum value of current at resonance |
| B. | Will change the resonance frequency |
| C. | Will change the impedance at resonance frequency |
| D. | Will increase the selectivity of the circuit |
| Answer» E. | |
| 144. |
At __________ frequencies the parallel R-L circuit behaves as purely resistive.$? |
| A. | Low |
| B. | Very low |
| C. | High |
| D. | Very high |
| Answer» E. | |
| 145. |
If two sine waves of the same frequency have a phase difference of JT radians, then$? |
| A. | Both will reach their minimum values at the same instant |
| B. | Both will reach their maximum values at the same instant |
| C. | When one wave reaches its maxi¬mum value, the other will reach its minimum value |
| D. | None of the above |
| Answer» D. None of the above | |
| 146. |
Inductance affects the direct current flow$? |
| A. | Only at the time of turning off |
| B. | Only at the time of turning on |
| C. | At the time of turning on and off |
| D. | At all the time of operation |
| Answer» D. At all the time of operation | |
| 147. |
Power factor of the system is kept high$? |
| A. | To reduce line losses |
| B. | To maximize the utilization of the capacities of generators, lines and transformers |
| C. | To reduce voltage regulation of the line |
| D. | Due to all above reasons |
| Answer» E. | |
| 148. |
In any A.C. circuit always$? |
| 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 | |
| 149. |
The r.m.s. value of a sinusoidal A.C. current is equal to its value at an angle of ________ degrees.? |
| A. | 90 |
| B. | 60 |
| C. | 45 |
| D. | 30 |
| Answer» D. 30 | |
| 150. |
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 | |