MCQOPTIONS
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MCQOPTIONS
This section includes 309 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 201. |
Most common form of A.C. meters met with in every day domestic and industrial installations are? |
| A. | mercury motor meters |
| B. | commutator motor meters |
| C. | induction type single phase energy meters |
| D. | all of the above |
| Answer» D. all of the above | |
| 202. |
The thermal conductivity of hydrogen is ______ times that of air? |
| A. | 2 |
| B. | 3 |
| C. | 5 |
| D. | 7 |
| Answer» E. | |
| 203. |
The resistance in the circuit of the moving coil of a dynamometer wattmeter should be? |
| A. | almost zero |
| B. | low |
| C. | high |
| D. | none of the above |
| Answer» D. none of the above | |
| 204. |
Wattmeter cannot be designed on the principle of? |
| A. | electrostatic instrument |
| B. | thermocouple instrument |
| C. | moving iron instrument |
| D. | electrodynamic instrument |
| Answer» D. electrodynamic instrument | |
| 205. |
With conventional hydrogen cooling it is possible to increase the rating of a single unit to? |
| A. | 50 MW |
| B. | 100 MW |
| C. | 200 MW |
| D. | none of the above |
| Answer» D. none of the above | |
| 206. |
Which of the following instruments indicate the instantaneous value of the electrical quantity being measured at the time at which it is being measured ?? |
| A. | Absolute instruments |
| B. | Indicating instruments |
| C. | Recording instruments |
| D. | Integrating instruments |
| Answer» C. Recording instruments | |
| 207. |
The value of exciting or magnetizing current depends upon which of the following factors ?? |
| A. | Total m.m.f. required |
| B. | The number of turns in the exciting winding |
| C. | The way in which the winding is distributed |
| D. | All of the above |
| Answer» E. | |
| 208. |
A moving-coil permanent-magnet instrument can be used as _____ by using a low resistance shunt.? |
| A. | ammeter |
| B. | voltmeter |
| C. | flux-meter |
| D. | ballistic galvanometer |
| Answer» B. voltmeter | |
| 209. |
The time taken by the machine to attain 0.632 of its final steady temperature rise is called? |
| A. | heating time constant |
| B. | cooling time constant |
| C. | either (A) or (B) |
| D. | none of the above |
| Answer» B. cooling time constant | |
| 210. |
The heat dissipating capability of transformers of ratings higher than 30 kVA in increased by providing which of the following?? |
| A. | Corrugations |
| B. | Fins |
| C. | Tubes |
| D. | All of the above |
| Answer» E. | |
| 211. |
The forced oil and air circulation method is usual one for transformers of capacities |
| A. | upto 5 MVA |
| B. | upto 10 MVA |
| C. | upto 20 MVA |
| D. | 30 MVA upwards |
| Answer» E. | |
| 212. |
The rectifier instrument is not free from |
| A. | temperature error |
| B. | wave shape error |
| C. | frequency error |
| D. | all of the above |
| Answer» D. all of the above | |
| 213. |
A _____ device prevents the oscillation of the moving system and enables the latter to reach its final position quickly |
| A. | deflecting |
| B. | controlling |
| C. | damping |
| D. | any of the above |
| Answer» D. any of the above | |
| 214. |
Machines cooled by direct cooling method may be called |
| A. | supercharged |
| B. | inner cooled |
| C. | conductor cooled |
| D. | any of the above |
| Answer» E. | |
| 215. |
Which of the following materials is used in the manufacture of resistance grids to be used in the starters of largemotors ? |
| A. | Copper |
| B. | Aluminium |
| C. | Steel |
| D. | Cast-iron |
| Answer» E. | |
| 216. |
In a vibrating reed frequency meter the natural frequencies of two adjacent reeds have a difference of |
| A. | 0.1 Hz |
| B. | 0.25 Hz |
| C. | 0.5 Hz |
| D. | 1.5 Hz |
| Answer» D. 1.5 Hz | |
| 217. |
The ratio of maximum displacement deviation to full scale deviation of the instrument is called |
| A. | static sensitivity |
| B. | dynamic deviation |
| C. | linearity |
| D. | precision or accuracy |
| Answer» D. precision or accuracy | |
| 218. |
The stator of a D.C. machine comprises of |
| A. | main poles |
| B. | interpoles |
| C. | frame |
| D. | all of the above |
| Answer» E. | |
| 219. |
________ has a lowrelative permeability and is used principally in field frames when cost is of primary importance and extra weight is not objectionable. |
| A. | Cast steel |
| B. | Aluminium |
| C. | Soft steel |
| D. | Cast iron |
| Answer» E. | |
| 220. |
The high voltage winding is usually which of the following type ? |
| A. | Cylindrical winding with circular conductors |
| B. | Cross-over winding with either circular or small rectangular conductors |
| C. | Continuous disc type winding with rectangular conductors |
| D. | All of the above types |
| Answer» E. | |
| 221. |
The gravity controlled instrument has crowded scale because current is proportional to |
| A. | balancing weight |
| B. | deflection angle |
| C. | sine of deflection angle |
| D. | All of the above |
| Answer» D. All of the above | |
| 222. |
Transformers with a capacity of up to _____ have a cooling radiator system with natural cooling |
| A. | 2 MVA |
| B. | 5 MVA |
| C. | 7.5 MVA |
| D. | 10 MVA |
| Answer» E. | |
| 223. |
The laminations of the armature of a D.C. machine are usually _____ thick. |
| A. | 0.1 to 0.2 mm |
| B. | 0.2 to 0.3 mm |
| C. | 0.3 to 0.4 mm |
| D. | 0.4 to 0.5 mm |
| Answer» E. | |
| 224. |
If an instrument has cramped scale for larger values, then it follows |
| A. | square law |
| B. | logarithmic law |
| C. | uniform law |
| D. | none of the above |
| Answer» C. uniform law | |
| 225. |
The length cf air gap to be provided in ______ is primarily determined by power factor consideration. |
| A. | d.c. series motor |
| B. | d.c. shunt motor |
| C. | induction motor |
| D. | synchronous motor |
| Answer» D. synchronous motor | |
| 226. |
Hydrogen has a heat transfer co-efficient _____ times that of air |
| A. | 1.5 |
| B. | 2.5 |
| C. | 3.5 |
| D. | 4.5 |
| Answer» B. 2.5 | |
| 227. |
A current density of _________ is used for large power transformers with forced circulation of oil or with water cooling coils |
| A. | 1.5 to 2.5 A/mm² |
| B. | 3.5 to 4.5 A/mm² |
| C. | 4.0 to 5.0 A/mm² |
| D. | 5.4 to 6.2 A/mm² |
| Answer» E. | |
| 228. |
In a 3-phase power measurement by two wattmeter method the reading of one of the wattmeter was zero. The power factor of the load must be |
| A. | unity |
| B. | 0.5 |
| C. | 0.3 |
| D. | zero |
| Answer» C. 0.3 | |
| 229. |
In a dynamometer 3-phase power factor meter, the planes of the two moving coils are at |
| A. | 0° |
| B. | 60° |
| C. | 90° |
| D. | 120° |
| Answer» E. | |
| 230. |
The weight of copper of both armature and field windings decreases with _____ in number of poles. |
| A. | increase |
| B. | decrease |
| C. | either of the above |
| D. | none of the above |
| Answer» B. decrease | |
| 231. |
An instrument transformer is used to extend the range of |
| A. | induction instrument |
| B. | electrostatic instrument |
| C. | moving coil instrument |
| D. | any of the above |
| Answer» B. electrostatic instrument | |
| 232. |
In a D.C. machine, the value of peripheral speed should not, normally, exceed |
| A. | 10 m/s |
| B. | 20 m/s |
| C. | 30 m/s |
| D. | 40 m/s |
| Answer» D. 40 m/s | |
| 233. |
In a Weston synchronoscope, the fixed coils are connected across |
| A. | bus-bars |
| B. | incoming alternator |
| C. | a lamp |
| D. | none of the above |
| Answer» C. a lamp | |
| 234. |
are used for construction of core of electromagnets. |
| A. | Soft magnetic materials |
| B. | Hard magnetic materials |
| C. | Either (A) or (B) |
| D. | None of the above |
| Answer» B. Hard magnetic materials | |
| 235. |
The cylindrical windings using circular conductors are used for current rating of |
| A. | upto 20 A |
| B. | upto 40 A |
| C. | upto 60 A |
| D. | upto 80 A |
| Answer» E. | |
| 236. |
For large power transformers, self oil cooled type or air blast type which of the following values of current density may be used? |
| A. | 1.0 to 1.2 A/mm² |
| B. | 1.5 to 2.0 A/mm² |
| C. | 2.2 to 3.2 A/mm² |
| D. | 3.2 to 4.2 A/mm² |
| Answer» D. 3.2 to 4.2 A/mm¬¨‚⧠| |
| 237. |
If an insulating material is operated beyond the maximum allowable temperature, its life is |
| A. | drastically increased |
| B. | drastically reduced |
| C. | unaffected |
| D. | none of the above |
| Answer» C. unaffected | |
| 238. |
_______ is extensively used for those portions of magnetic circuit which carry steady flux and need superior mechanical properties ? |
| A. | Grey cast-iron |
| B. | Cast steel |
| C. | High carbon steel |
| D. | Stainless steel |
| Answer» C. High carbon steel | |
| 239. |
Cylindrical windings using circular conductors, employed in transformers, are |
| A. | single layered |
| B. | double layered |
| C. | multi-layered |
| D. | none of the above |
| Answer» D. none of the above | |
| 240. |
The slot leakage can be calculated by making which of the following assumptions ? |
| A. | The current in the slot conductors is uniformly distributed over their cross-section |
| B. | The leakage path is straight across the slot and around the iron at the bottom |
| C. | The permanence of air paths is only considered. The reluctance of iron paths is assumed as zero |
| D. | All of the above |
| Answer» E. | |
| 241. |
Which of the following methods is most accurate ? |
| A. | Equivalent current method |
| B. | Equivalent power method |
| C. | Equivalent torque method |
| D. | Method of average losses |
| Answer» B. Equivalent power method | |
| 242. |
Alternating current is measured by |
| A. | induction ammeter |
| B. | permanent magnet type ammeter |
| C. | electrostatic ammeter |
| D. | moving iron repulsion type voltmeter |
| Answer» B. permanent magnet type ammeter | |
| 243. |
Damping of the Ballistic galvanometer is made small to |
| A. | get first deflection large |
| B. | make the system oscillatory |
| C. | make the system critically damped |
| D. | get minimum overshoot |
| Answer» B. make the system oscillatory | |
| 244. |
A direct current can be measured by |
| A. | a D.C. potentiometer directly |
| B. | a D.C. potentiometer in conjunction with a standard resistance |
| C. | a D.C. potentiometer in conjunction with a volt ratio box |
| D. | none of the above |
| Answer» C. a D.C. potentiometer in conjunction with a volt ratio box | |
| 245. |
Helical windings are used in |
| A. | distribution transformers |
| B. | power transformers |
| C. | shell type transformers |
| D. | none of the above |
| Answer» C. shell type transformers | |
| 246. |
Murray loop test can be used for location of |
| A. | ground fault on a cable |
| B. | short circuit fault on a cable |
| C. | both the ground fault and the short-circuit fault |
| D. | none of the above |
| Answer» D. none of the above | |
| 247. |
Tractive magnets are operated from |
| A. | a.c. supply |
| B. | d.c. supply |
| C. | either a.c. or d.c. supply |
| D. | none of the above |
| Answer» D. none of the above | |
| 248. |
Various adjustments in an energy meter include |
| A. | light load or friction |
| B. | lag and creep |
| C. | overload and voltage compensation |
| D. | temperature compensation |
| E. | all of the above |
| Answer» F. | |
| 249. |
Power transformers should be designed to have maximum efficiency |
| A. | at one-fourth load |
| B. | at one-half load |
| C. | at or near full load |
| D. | any of the above |
| Answer» D. any of the above | |
| 250. |
Which of the following problem arises in D.C. motors which are fed from thyristor bridge circuits ? |
| A. | Increased I R losses |
| B. | Increased core losses |
| C. | Poor commutation |
| D. | Change in motor parameters |
| E. | All of the above |
| Answer» F. | |