MCQOPTIONS
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MCQOPTIONS
This section includes 715 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering Questions knowledge and support exam preparation. Choose a topic below to get started.
| 101. |
The insulation resistance of a cable of length 10 km is 1M Ω . For a length of 100 km of the same cable, what will be the insulation resistance? |
| A. | 1 M Ω |
| B. | 10 M Ω |
| C. | 0.1 M Ω |
| D. | 0.01 M Ω |
| Answer» D. 0.01 M Ω | |
| 102. |
What is the main drawback of using paper as the insulating material? |
| A. | Is hygroscopic |
| B. | Has poor dielectric strength |
| C. | Has a very low insulation resistivity |
| D. | Has high capacitance |
| Answer» B. Has poor dielectric strength | |
| 103. |
What is the safe working temperature for a conductor in case of armoured cables? |
| A. | 50° C |
| B. | 75° C |
| C. | 65° C |
| D. | 40° C |
| Answer» D. 40° C | |
| 104. |
What is the horizontal spacing between phase conductors of 132 kV line? |
| A. | 8 m. |
| B. | 11 m. |
| C. | 14 m. |
| D. | 17 m. |
| Answer» B. 11 m. | |
| 105. |
Which type of insulator is used on 132 kV transmission lines? |
| A. | Pin type |
| B. | Disc type |
| C. | Shackle type |
| D. | Pin and shackle type |
| Answer» C. Shackle type | |
| 106. |
What is the minimum clearance provided for the 132 kV line from the ground? |
| A. | 3.2 m. |
| B. | 6.4 m. |
| C. | 7.5 m. |
| D. | 10.5 m. |
| Answer» C. 7.5 m. | |
| 107. |
What is the desirable safety factor prescribed for the pin type of insulators? |
| A. | 5 |
| B. | 13 |
| C. | 10 |
| D. | 2 |
| Answer» D. 2 | |
| 108. |
Why is the voltage rating of a multiple shell pin type insulator cannot be increased beyond a limiting value? |
| A. | The internal voltage distribution between shells becomes unequal |
| B. | The leakage path resistance starts reducing |
| C. | The disruptive critical voltage for the material of the insulator is reached |
| D. | The puncture voltage of the material of the insulator is reached |
| Answer» B. The leakage path resistance starts reducing | |
| 109. |
Where are the strain type insulators used? |
| A. | At dead ends |
| B. | At any intermediate anchor tower |
| C. | On straight runs |
| D. | Either (a) or (b) |
| Answer» E. | |
| 110. |
What is the dielectric strength of porcelain? |
| A. | 55 kV/cm. |
| B. | 60 kV/cm. |
| C. | 75 kV/cm. |
| D. | 80 kV/cm. |
| Answer» C. 75 kV/cm. | |
| 111. |
Porcelain is produced by firing at high temperature due to mixtures of _________. |
| A. | Kaolin |
| B. | Feldspar |
| C. | Quartz |
| D. | All of these |
| Answer» E. | |
| 112. |
Why is the wavy structure of pin insulators used? |
| A. | Increases mechanical strength |
| B. | Increases puncture strength |
| C. | Increases flash over voltage |
| D. | Increases thermal strength |
| Answer» D. Increases thermal strength | |
| 113. |
The number of discs in a string of insulators for 400 kV ac over head transmission line lies in the range of |
| A. | 32 – 33 |
| B. | 22 – 23 |
| C. | 15 – 16 |
| D. | 9 – 10 |
| Answer» C. 15 – 16 | |
| 114. |
What is the maximum voltage level upto which the pin type insulators can be used? |
| A. | 22 kV |
| B. | 33 kV |
| C. | 66 kV |
| D. | 132 kV |
| Answer» C. 66 kV | |
| 115. |
What is the safety factor of an insulator? |
| A. | Puncture strength * Flash over voltage |
| B. | Puncture strength / Flash over voltage |
| C. | Flash over voltage / Puncture strength |
| D. | None of these |
| Answer» C. Flash over voltage / Puncture strength | |
| 116. |
What is the source of heat generation in cables? |
| A. | Copper loss in conductor |
| B. | Dielectric losses in cable insulation |
| C. | Losses in metallic sheathings and armouring |
| D. | All of these |
| Answer» E. | |
| 117. |
The capacitances of a 3 phase belted cable are 12.6 μ F between the three cores bunched together and the lead sheath and 7.4 μ F between one core and the other two connected to sheath. What will be the charging current drawn by the cable when connected to a 66 kV supply? |
| A. | 100 A |
| B. | 99.3648 A |
| C. | 105.236 A |
| D. | 107.74 A |
| Answer» E. | |
| 118. |
Which type of insulators is mainly used for low voltage overhead lines? |
| A. | Pin type |
| B. | Shackle type |
| C. | Suspension type |
| D. | None of these |
| Answer» C. Suspension type | |
| 119. |
Where the radial systems are generally employed? |
| A. | Where power is generated at low voltage |
| B. | Where power is generated at high voltage |
| C. | Where power is generated at low voltage and substation is located at the centre of the load |
| D. | Where power is generated at high voltage and substation is located at the centre of the load |
| Answer» D. Where power is generated at high voltage and substation is located at the centre of the load | |
| 120. |
Name the cable which connects the distributor to the consumer terminals. |
| A. | Distributors |
| B. | Service mains |
| C. | Feeders |
| D. | All of these |
| Answer» C. Feeders | |
| 121. |
Which component connects the substation to the area where power is to be distributed? |
| A. | Distributors |
| B. | Service mains |
| C. | Feeders |
| D. | All of these |
| Answer» D. All of these | |
| 122. |
What is the main type of distribution system in India? |
| A. | Radial |
| B. | Parallel |
| C. | Network |
| D. | All of these |
| Answer» B. Parallel | |
| 123. |
As the moisture content in the air increases, what is the effect of this on the disruptive critical voltage? |
| A. | Increases |
| B. | Decreases |
| C. | Remains constant |
| D. | May increases or decrease |
| Answer» C. Remains constant | |
| 124. |
Air density factor which depends on the pressure and temperature is given by which of these formulas? |
| A. | δ = (5.92 * b) / (273 + t) |
| B. | δ = (7.92 * b) / (273 + t) |
| C. | δ = (3.92 * b) / (273 + t) |
| D. | δ = (4.92 * b) / (273 + t) |
| Answer» D. δ = (4.92 * b) / (273 + t) | |
| 125. |
What is the main advantage of ring main system over radial system? i. Voltage drop in the feeder is less. ii. Power factor is higher. iii. Supply is more reliable. Which among the above statements are correct? |
| A. | i and ii only |
| B. | ii and iii only |
| C. | i and iii only |
| D. | i, ii and iii |
| Answer» D. i, ii and iii | |
| 126. |
What is the permissible limit of voltage variations allowed in the distribution systems? |
| A. | ± 2 % |
| B. | ± 5 % |
| C. | ± 10 % |
| D. | ± 6 % |
| Answer» E. | |
| 127. |
Which among the following cables are generally suited for the voltages upto 11 kV? |
| A. | Belted cables |
| B. | Screened cables |
| C. | Pressure cables |
| D. | None of these |
| Answer» B. Screened cables | |
| 128. |
Which type of distribution is preferred in residential areas? |
| A. | Single phase, two wire |
| B. | Three phase, three wire |
| C. | Three phase, four wire |
| D. | Two phase, four wire |
| Answer» D. Two phase, four wire | |
| 129. |
Why are the balancers fields cross connected in a three wire distribution system? |
| A. | Equalise voltage on positive and negative outer |
| B. | Boost the generated voltage |
| C. | Make both machines operate as unloaded motors |
| D. | All of these |
| Answer» B. Boost the generated voltage | |
| 130. |
Assembly of which type of insulators are used as strain type of insulators? |
| A. | Pin type |
| B. | Shackle type |
| C. | Suspension type |
| D. | None of these |
| Answer» D. None of these | |
| 131. |
Why are the boosters inserted in the circuit? |
| A. | Reduce current |
| B. | Increase current |
| C. | Reduce voltage drop |
| D. | Compensate for voltage drop |
| Answer» E. | |
| 132. |
On what factor does the string efficiency of a string of suspension insulators is dependent? |
| A. | Size of the insulator |
| B. | Number of discs in the string |
| C. | Size of tower |
| D. | None of these |
| Answer» C. Size of tower | |
| 133. |
The types of suspension insulators are |
| A. | Hewlett type |
| B. | Inter linking type |
| C. | Cemented cap type |
| D. | All of these |
| Answer» E. | |
| 134. |
Post type insulators are generally used in lines operating |
| A. | Above 100 kV |
| B. | Below 33 kV |
| C. | At any voltage level |
| D. | None of these |
| Answer» D. None of these | |
| 135. |
The stay type of insulators is insulated at a height of not less than _________ m. |
| A. | 5 |
| B. | 6 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 136. |
Which type of insulators is used in guy wires? |
| A. | Stay insulators |
| B. | Shackle insulators |
| C. | Pin type |
| D. | Strain type |
| Answer» B. Shackle insulators | |
| 137. |
Assertion (A): Glazing on ceramic insulators is done to make it smooth and non – absorbent. Reason (R): Moisture from atmosphere collects on the surface causing electrical breakdown. |
| A. | Both A and R are true and R is the correct explanation of A |
| B. | Both A and R are true and R is not the explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» B. Both A and R are true and R is not the explanation of A | |
| 138. |
For a short line if the receiving end voltage is equal to sending end voltage under loaded conditions |
| A. | The sending end power factor is unity. |
| B. | The receiving end power factor is unity. |
| C. | The sending end power factor is leading. |
| D. | The receiving end power factor is leading. |
| Answer» E. | |
| 139. |
The ABCD constants of a 3 phase transposed transmission line with linear and passive elements ________________. |
| A. | are always equal |
| B. | never equal |
| C. | only A and D are equal |
| D. | only B and C are equal |
| Answer» D. only B and C are equal | |
| 140. |
The insulators fail due to |
| A. | Flash over |
| B. | Short circuits |
| C. | Deposition of dust |
| D. | All of these |
| Answer» E. | |
| 141. |
The maximum voltage of the disc type insulators is at |
| A. | Same at all points |
| B. | Near the tower or starting of the insulator |
| C. | Near to the conductors |
| D. | None of these |
| Answer» D. None of these | |
| 142. |
The number of discs required for 220 kV ac over head transmission line in clear atmosphere is |
| A. | 10 – 12 |
| B. | 21 – 22 |
| C. | 12 – 14 |
| D. | 5 – 6 |
| Answer» D. 5 – 6 | |
| 143. |
At what angle is the water sprayed on the insulator in 50 cycle wet test? |
| A. | 35 °C |
| B. | 40 °C |
| C. | 45 °C |
| D. | 50 °C |
| Answer» D. 50 °C | |
| 144. |
What is the value of the wave front and the wave tail of the standard lightning impulse wave used in the impulse voltage withstand test? |
| A. | 50 μ sec and 1.2 μ sec |
| B. | 1.2 μ sec and 50 μ sec |
| C. | 50 μ sec and 2.1 μ sec |
| D. | 2.1 μ sec and 50 μ sec |
| Answer» C. 50 μ sec and 2.1 μ sec | |
| 145. |
What is corona? |
| A. | Partial breakdown of air |
| B. | Complete breakdown of air |
| C. | Sparking between the lines |
| D. | None of these |
| Answer» C. Sparking between the lines | |
| 146. |
What happens if the voltage applied is equal to the critical disruptive voltage? |
| A. | Corona does not start |
| B. | Corona starts but is not visible |
| C. | Corona starts and is visible |
| D. | Only ionization starts |
| Answer» C. Corona starts and is visible | |
| 147. |
In case of dc voltage, which colour beads are formed near the negative conductor? |
| A. | Reddish |
| B. | Bluish |
| C. | Greenish |
| D. | Violet |
| Answer» B. Bluish | |
| 148. |
In which climate does the chances of occurrence of corona is maximum? |
| A. | Dry |
| B. | Hot summer |
| C. | Winter |
| D. | Humid |
| Answer» E. | |
| 149. |
What is the effect on corona, if the spacing between the conductors is increased? |
| A. | Corona increases |
| B. | Corona is absent |
| C. | Corona decreases |
| D. | None of these |
| Answer» C. Corona decreases | |
| 150. |
In which of the transmission systems is the skin effect observed? |
| A. | Cable carrying dc current |
| B. | DC transmission line only |
| C. | AC transmission line only |
| D. | DC as well as AC transmission lines |
| Answer» D. DC as well as AC transmission lines | |