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.
| 151. |
In a pure resistive circuit? |
| A. | Current lags behind the voltage by 90° |
| B. | Current leads the voltage by 90° |
| C. | Current can lead or lag the voltage by 90° |
| D. | Current is in phase with the voltage |
| Answer» E. | |
| 152. |
Poor power factor? |
| A. | Reduces load handling capability of electrical system |
| B. | Results in more power losses in the electrical system |
| C. | Overloads alternators, transformers and distribution lines |
| D. | Results in all above |
| Answer» E. | |
| 153. |
Ohm is unit of all of the following except? |
| A. | Inductive reactance |
| B. | Capacitive reactance |
| C. | Resistance |
| D. | Capacitance |
| Answer» E. | |
| 154. |
In a circuit containing R, L and C, power loss can take place in? |
| A. | C only |
| B. | L only |
| C. | R only |
| D. | All above |
| Answer» D. All above | |
| 155. |
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 | |
| 156. |
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 | |
| 157. |
The equation of 50 Hz current sine wave having r.m.s. value of 60 A is? |
| A. | 60 sin 25 t |
| B. | 60 sin 50 t |
| C. | 84.84 sin 3141 |
| D. | 42.42 sin 314 t |
| Answer» D. 42.42 sin 314 t | |
| 158. |
A phasor is? |
| A. | A line which represents the magnitude and phase of an alternating quantity |
| B. | A line representing the magnitude and direction of an alternating quantity |
| C. | A colored tag or band for distinction between different phases of a 3-phase supply |
| D. | An instrument used for measuring phases of an unbalanced 3-phase load |
| Answer» B. A line representing the magnitude and direction of an alternating quantity | |
| 159. |
Inductance of coil |
| A. | Is unaffected by the supply frequency |
| B. | Decreases with the increase in supply frequency |
| C. | Increases with the increase in supply frequency |
| D. | Becomes zero with the increase in supply frequency |
| Answer» D. Becomes zero with the increase in supply frequency | |
| 160. |
Which of the following circuit component opposes the change in the circuit voltage ? |
| A. | Inductance |
| B. | Capacitance |
| C. | Conductance |
| D. | Resistance |
| Answer» C. Conductance | |
| 161. |
The apparent power drawn by an A.C. circuit is 10 kVA and active power is 8 kW. The reactive power in the circuit is |
| A. | 4 kVAR |
| B. | 6 kVAR |
| C. | 8 kVAR |
| D. | 16 kVAR |
| Answer» C. 8 kVAR | |
| 162. |
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 | |
| 163. |
In each of the three coils of a three phase generator, an alternating voltage having an r.m.s. value of 220 V is induced. Which of the following values is indicated by the voltmeters? |
| A. | 220 V |
| B. | 220 v3 V |
| C. | 220/v3 V |
| D. | None of the above |
| Answer» B. 220 v3 V | |
| 164. |
A heater is rated as 230 V, 10 kW, A.C. The value 230 V refers to |
| A. | Average voltage |
| B. | r.m.s. voltage |
| C. | Peak voltage |
| D. | None of the above |
| Answer» C. Peak voltage | |
| 165. |
In a parallel R-C circuit, the current always _________the applied voltage |
| A. | Lags |
| B. | Leads |
| C. | Remains in phase with |
| D. | None of the above |
| Answer» C. Remains in phase with | |
| 166. |
In a series resonant circuit, the impedance of the circuit is |
| A. | Minimum |
| B. | Maximum |
| C. | Zero |
| D. | None of the above |
| Answer» B. Maximum | |
| 167. |
Power factor of electric bulb is |
| A. | Zero |
| B. | Lagging |
| C. | Leading |
| D. | Unity |
| Answer» E. | |
| 168. |
The power is measured in terms of decibels in case of |
| A. | Electronic equipment |
| B. | Transformers |
| C. | Current transformers |
| D. | Auto transformers |
| Answer» B. Transformers | |
| 169. |
The r.m.s. value and mean value is the same in the case of |
| A. | Triangular wave |
| B. | Sine wave |
| C. | Square wave |
| D. | Half wave rectified sine wave |
| Answer» D. Half wave rectified sine wave | |
| 170. |
The reactance offered by a capacitor to alternating current of frequency 50 Hz is 20 Q. If frequency is increased to 100 Hz, reactance becomes __________ ohms. |
| A. | 2.5 |
| B. | 5 |
| C. | 10 |
| D. | 15 |
| Answer» D. 15 | |
| 171. |
In a pure inductive circuit |
| A. | The current is in phase with the voltage |
| B. | The current lags behind the voltage by 90° |
| C. | The current leads the voltage by 90° |
| D. | The current can lead or lag by 90° |
| Answer» C. The current leads the voltage by 90¬¨‚àû | |
| 172. |
An A.C. voltage is impressed across a pure resistance of 3.5 ohms in parallel with a pure inductance of impedance of 3.5 ohms, |
| A. | The current through the resistance is more |
| B. | The current through the resistance is less |
| C. | Both resistance and inductance carry equal currents |
| D. | None of the above |
| Answer» D. None of the above | |
| 173. |
For a sine wave with peak value Emax ___________ 8.30. the average value is |
| A. | 0.636 Emax |
| B. | 0.707 Emax |
| C. | 0.434 EWc |
| D. | lAUEmax |
| Answer» B. 0.707 Emax | |
| 174. |
In a series L-C circuit at the resonant frequency the |
| A. | Current is maximum |
| B. | Current is minimum |
| C. | Impedance is maximum |
| D. | Voltage across C is minimum |
| Answer» B. Current is minimum | |
| 175. |
Which of the following refers to a parallel circuit? |
| A. | The current through each element is same |
| B. | The voltage across element is in proportion to it's resistance value |
| C. | The equivalent resistance is greater than any one of the resistors |
| D. | The current through any one element is less than the source current |
| Answer» E. | |
| 176. |
The peak value of a sine wave is 200 V. Its average value is |
| A. | 127.4 V |
| B. | 141.4 V |
| C. | 282.8 V |
| D. | 200 V |
| Answer» B. 141.4 V | |
| 177. |
All the rules and laws of D.C. circuit also apply to A.C. circuit containing |
| A. | Capacitance only |
| B. | Inductance only |
| C. | Resistance only |
| D. | All above |
| Answer» D. All above | |
| 178. |
In a R-L-C circuit |
| A. | Power is consumed in resistance and is equal to IR |
| B. | Exchange of power takes place between inductor and supply line |
| C. | Exchange of power takes place between capacitor and supply line |
| D. | All above are correct |
| Answer» E. | |
| 179. |
In R-L-C series resonant circuit magnitude of resonance frequency can be changed by changing the value of |
| A. | R only |
| B. | L only |
| C. | C only |
| D. | L or C |
| Answer» E. | |
| 180. |
If a sinusoidal wave has frequency of 50 Hz with 30 A r.m.s. current which of the following equation represents this wave? |
| A. | 42.42 sin 314 t |
| B. | 60 sin 25 t |
| C. | 30 sin 50 t |
| D. | 84.84 sin 25 t |
| Answer» B. 60 sin 25 t | |
| 181. |
The r.m.s. value of pure cosine function is |
| A. | 0.5 of peak value |
| B. | 0.707 of peak value |
| C. | Same as peak value |
| D. | Zero |
| Answer» C. Same as peak value | |
| 182. |
The form factor is the ratio of |
| A. | Peak value to r.m.s. value |
| B. | r.m.s. value to average value |
| C. | Average value to r.m.s. value |
| D. | None of the above |
| Answer» C. Average value to r.m.s. value | |
| 183. |
The phase difference between voltage and current wave through a circuit element is given as 30°. The essential condition is that# |
| A. | Both waves must have same frequency |
| B. | Both waves must have identical peak values |
| C. | Both waves must have zero value at the same time |
| D. | None of the above |
| Answer» B. Both waves must have identical peak values | |
| 184. |
Skin effect occurs when a conductor carries current at _________ frequencies. |
| A. | Very low |
| B. | Low |
| C. | Medium |
| D. | High |
| Answer» E. | |
| 185. |
A pure inductance connected across 250 V, 50 Hz supply consumes 100 W. This consumption can be attributed to |
| A. | The big size of the inductor |
| B. | The reactance of the inductor |
| C. | The current flowing in the inductor |
| D. | The statement given is false |
| Answer» E. | |
| 186. |
The double energy transient occur in the |
| A. | Purely inductive circuit |
| B. | R-L circuit |
| C. | R-C circuit |
| D. | R-L-C circuit |
| Answer» E. | |
| 187. |
In a three-phase supply floating neutral is undesirable because it way give rise to |
| A. | High voltage across the load |
| B. | Low voltage across the load |
| C. | Unequal line voltages across the load |
| D. | None of these |
| Answer» D. None of these | |
| 188. |
Which of the following coil will have large resonant frequency? |
| A. | A coil with large resistance |
| B. | A coil with low resistance |
| C. | A coil with large distributed capacitance |
| D. | A coil with low distributed capacitance |
| Answer» D. A coil with low distributed capacitance | |