MCQOPTIONS
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MCQOPTIONS
This section includes 517 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 301. |
An overhead line is equipped with shunt inductive reactor at receiving end to maintain sending end voltage equal to the receiving end voltage. If the ABCD parameters of line are A = D = 0.9 ∠0, B = 200 ∠90 Ω and C = 0.95 × 10-3 ∠90 s, what should be the ohmic value of the reactor to maintain same voltage on both sides? |
| A. | 1055 Ω |
| B. | 105.26 Ω |
| C. | 2000 Ω |
| D. | 1052.6 Ω |
| Answer» D. 1052.6 Ω | |
| 302. |
______ Specifies the safe voltage that the insulation of a cable can withstand. |
| A. | Minimum operating voltage |
| B. | Nominal operating voltage |
| C. | Voltage grading of cables |
| D. | Specific voltage of cables |
| Answer» D. Specific voltage of cables | |
| 303. |
Grounding is generally done in transmission line at |
| A. | The supply end |
| B. | The receiving end |
| C. | Middle of the line |
| D. | Anywhere |
| Answer» B. The receiving end | |
| 304. |
In an HVDC transmission mode, the link which has two circuits that are almost independent of each other is called |
| A. | Monopolar link |
| B. | Bipolar link |
| C. | Homopolar link |
| D. | Dualpolar link |
| Answer» C. Homopolar link | |
| 305. |
Loss-tangent in plane waves in lossy dielectrics will be |
| A. | proportional to the Y component of the magnetic field intensity (HY) |
| B. | inversely proportional to the Y component of the magnetic field intensity (HY) |
| C. | inversely proportional to the X component of the magnetic field intensity (HX) |
| D. | proportional to X component of the magnetic field intensity (HX) |
| Answer» D. proportional to X component of the magnetic field intensity (HX) | |
| 306. |
For household wiring and small units, the following should be used as a safety measure: |
| A. | MCB |
| B. | OCB |
| C. | ACB |
| D. | MCCB |
| Answer» B. OCB | |
| 307. |
Bundled conductors are mainly used in high voltage overhead transmission lines to |
| A. | Reduce line loss |
| B. | Reduce harmonics |
| C. | Reduce corona |
| D. | Increase strength |
| Answer» D. Increase strength | |
| 308. |
In SCADA system network, the Repeaters are used to increase the |
| A. | length of transmission data |
| B. | coverage range of transmission data |
| C. | distortion of transmission data |
| D. | noise of transmission data |
| Answer» C. distortion of transmission data | |
| 309. |
Corona discharge is generally ________ in colour: |
| A. | Blackish |
| B. | Bluish |
| C. | Yellowish |
| D. | Brownish |
| Answer» C. Yellowish | |
| 310. |
Different types of line supports used for transmission lines include |
| A. | RCC and PCC poles |
| B. | steel towers |
| C. | steel poles |
| D. | wooden poles, steel poles, RCC and PCC poles and steel towers |
| Answer» C. steel poles | |
| 311. |
As per Indian Electricity rule in overhead systems, the recommended span in case of wooden poles is ______. |
| A. | 100-300 meters |
| B. | 40-50 meters |
| C. | 50-80 meters |
| D. | 80-100 meters |
| Answer» C. 50-80 meters | |
| 312. |
For exact compensation of voltage drop in the feeder, the booster must |
| A. | be earthed |
| B. | work on line voltage |
| C. | work on its linear portion of V-I characteristics |
| D. | work on its non-linear portion of V-I characteristics |
| Answer» D. work on its non-linear portion of V-I characteristics | |
| 313. |
In an underground cable, insulating material used is ______. |
| A. | Oil impregnated paper |
| B. | PVC |
| C. | Rubber |
| D. | Any of these |
| Answer» E. | |
| 314. |
A single core cable has a conductor of a diameter of 3 cm and the inside diameter of the lead sheath is 6 cm. If the cable is designed for an operating voltage of 33 kV (line to neutral). Then the minimum stress in the insulation of the cable is _________(Given ln 2 = 0.693). |
| A. | 39.90 kV/cm |
| B. | 22.44 kV/cm |
| C. | 35.08 kV/cm |
| D. | 19.90 kV/cm |
| Answer» C. 35.08 kV/cm | |
| 315. |
In a long transmission line with r, l, g and c are the resistance, inductance, shunt conductance and capacitance per unit length, respectively, the condition for distortion less transmission is |
| A. | rc = lg |
| B. | \(r = \sqrt {l/c} \) |
| C. | rg = lc |
| D. | \(g = \sqrt {c/l}\) |
| Answer» B. \(r = \sqrt {l/c} \) | |
| 316. |
A uniformly loaded DC distributor is fed at both ends with equal voltages. As compared to a similar distributor fed at one end only, the drop at the middle point is: |
| A. | Twice |
| B. | Half |
| C. | One-Fourth |
| D. | One-third |
| Answer» D. One-third | |
| 317. |
For demand side management, the power factor controlling equipment is placed |
| A. | At generating station |
| B. | Near transformer |
| C. | Near the apparatus responsible for low P.F. |
| D. | Near bus bar |
| Answer» D. Near bus bar | |
| 318. |
If the length of a wire is doubled, what will be its insulation resistance? |
| A. | will be reduced by 50% |
| B. | will be reduced by 25% |
| C. | will increase by 25% |
| D. | will increase by 50% |
| Answer» B. will be reduced by 25% | |
| 319. |
Capacitance grading of cable means |
| A. | Use of dielectrics in different concentrations |
| B. | Introduction of capacitances at various lengths of cable to counter the effect of inductance. |
| C. | Use of dielectrics of different permittivities. |
| D. | Grading according to capacitance per km length of the cable. |
| Answer» D. Grading according to capacitance per km length of the cable. | |
| 320. |
For overhead transmission line, the magnitude of surge impedance is close to: |
| A. | 4 - 6 Ω |
| B. | 50 -100 Ω |
| C. | 400 - 600 Ω |
| D. | 700 - 1000 Ω |
| Answer» D. 700 - 1000 Ω | |
| 321. |
Normally the human body resistance in totally wet and dry condition is ________ respectively. |
| A. | 1 kΩ and 1 MΩ |
| B. | 0.1 Ω and 10 kΩ |
| C. | 100 Ω and 1 kΩ |
| D. | 100 Ω and 10 kΩ |
| Answer» B. 0.1 Ω and 10 kΩ | |
| 322. |
In river crossings, modern high voltage lines have a span length of: |
| A. | more than 200 m but less than 400 m |
| B. | more than 400 m but less than 800 m |
| C. | more than 100 m but less than 200 m |
| D. | more than 800 m |
| Answer» E. | |
| 323. |
If the inductance of a line increases, transmission capacity will |
| A. | Increase |
| B. | Decrease |
| C. | Remains same |
| D. | Independent of inductance |
| Answer» C. Remains same | |
| 324. |
For a fixed receiving end and sending end voltage in a transmission system, what is the locus of the constant power? |
| A. | A straight line |
| B. | An ellipse |
| C. | A parabola |
| D. | A circle |
| Answer» E. | |
| 325. |
Pin insulators are never used for voltages above _______. |
| A. | 33 kV |
| B. | 22 kV |
| C. | 11 kV |
| D. | 1.1 kV |
| Answer» B. 22 kV | |
| 326. |
A protective device, which reduces the steepness of wave in front of a surge by absorbing surge energy, is called: |
| A. | Surge diverters |
| B. | Surge absorbers |
| C. | Switching surges |
| D. | Earthing screen |
| Answer» C. Switching surges | |
| 327. |
A string insulator has 4 units. The voltage across the bottom-most unit is 33.33% of the total voltage. Its string efficiency is |
| A. | 25% |
| B. | 33.33% |
| C. | 66.67% |
| D. | 75% |
| Answer» E. | |
| 328. |
An alternator is supplying a load of 300 kW at 0.6 p.f. lagging. If the power factor is raised to unity, how many more kilowatts can alternator supply for the same kVA loading? |
| A. | 100 kW |
| B. | 50 kW |
| C. | 200 kW |
| D. | 25 kW |
| Answer» D. 25 kW | |
| 329. |
Identify the block diagram given below: |
| A. | Meter distribution board |
| B. | Meter installation board |
| C. | Meter generation board |
| D. | Meter transmission board |
| Answer» B. Meter installation board | |
| 330. |
Pin type insulators are employed up to: |
| A. | 11 kV |
| B. | 33 kV |
| C. | 66 kV |
| D. | 132 kV |
| Answer» C. 66 kV | |
| 331. |
In case of transmission line conductors, with the increase in atmospheric temperature |
| A. | Length increases but stress decreases |
| B. | Length increases and stress also increases |
| C. | Length decreases but stress increases |
| D. | Both length as well as stress decreases |
| Answer» B. Length increases and stress also increases | |
| 332. |
A dc 3-wire distributor system requires how much of copper as compared with a dc 2-wire distributor system? |
| A. | Only 33.33% |
| B. | Only 66.66% |
| C. | Only 5/6 |
| D. | Only 5/16 |
| Answer» E. | |
| 333. |
Let W be the weight per unit length of the conductor, H be the horizontal tension, and l be the span length, then the sag in a freely suspended conductor is determined as: |
| A. | \(\delta = \frac{{W{l}}}{{8H}}\) |
| B. | \(\delta = \frac{{W{l}}}{{4H}}\) |
| C. | \(\delta = \frac{{W{l^2}}}{{8H}}\) |
| D. | \(\delta = \frac{{W{l^2}}}{{4H}}\) |
| Answer» D. \(\delta = \frac{{W{l^2}}}{{4H}}\) | |
| 334. |
Overhead system can be designed for operation up to |
| A. | 11 kV |
| B. | 33 kV |
| C. | 66 kV |
| D. | 400 kV |
| Answer» E. | |
| 335. |
In aluminium conductors, steel core is provided to |
| A. | Compensate for skin effect |
| B. | Neutralise proximity effect |
| C. | Reduce line inductance |
| D. | Increase the tensile strength |
| Answer» E. | |
| 336. |
The frequency of voltage generated, in case of generators, can be increased by |
| A. | Using reactors |
| B. | Increasing the load |
| C. | Adjusting the governor |
| D. | Reducing the terminal voltage |
| Answer» D. Reducing the terminal voltage | |
| 337. |
jCorona usually occurs when the electrostatic stress in air around the conductor exceeds |
| A. | 6.6 kV (r.m.s. value)/cm |
| B. | 11 kV (r.m.s. value)/cm |
| C. | 22 kV (maximum value)/cm |
| D. | 30 kV (maximum value)/cm |
| Answer» E. | |
| 338. |
Which of the following bus-bar schemes has the lowest cost? |
| A. | Ring bus-bar scheme |
| B. | Single bus-bar scheme |
| C. | Breaker and a half scheme |
| D. | Main and transfer scheme |
| Answer» C. Breaker and a half scheme | |
| 339. |
The material generally used for armour of high voltage cables is |
| A. | Aluminium |
| B. | Steel |
| C. | Brass |
| D. | Copper |
| Answer» C. Brass | |
| 340. |
The material commonly used for insulation in high voltage cables is |
| A. | Lead |
| B. | Paper |
| C. | Rubber |
| D. | None of the above |
| Answer» C. Rubber | |
| 341. |
The distributors for residential areas are |
| A. | Single phase |
| B. | Three-phase three wire |
| C. | Three-phase four wire |
| D. | None of the above |
| Answer» D. None of the above | |
| 342. |
In the analysis of which of the following lines shunt capacitance is neglected? |
| A. | Short transmission lines |
| B. | Medium transmission lines |
| C. | Long transmission lines |
| D. | Medium as well as long transmission lines |
| Answer» B. Medium transmission lines | |
| 343. |
Galvanized steel wire is generally used as |
| A. | Stay wire |
| B. | Earth wire |
| C. | Structural components |
| D. | All of the above |
| Answer» E. | |
| 344. |
In a tap changing transformer, the tappings are provided on |
| A. | Primary winding |
| B. | Secondary winding |
| C. | High voltage winding |
| D. | Any of the above |
| Answer» D. Any of the above | |
| 345. |
310 km line is considered as |
| A. | A long line |
| B. | A medium line |
| C. | A short line |
| D. | Any of the above |
| Answer» B. A medium line | |
| 346. |
When a live conductor of public electric supply breaks down and touches the earth which of the following will happen? |
| A. | Current will flow to earth |
| B. | Supply voltage will drop |
| C. | Supply voltage will increase |
| D. | No current will flow in the conductor |
| Answer» B. Supply voltage will drop | |
| 347. |
Constant voltage transmission entails the following disadvantage |
| A. | Large conductor area is required for same power transmission |
| B. | Short-circuit current of the system is increased |
| C. | Either of the above |
| D. | None of the above |
| Answer» C. Either of the above | |
| 348. |
The voltage regulation in magnetic amplifier type voltage regulator is effected by |
| A. | Electromagnetic induction |
| B. | Varying the resistance |
| C. | Varying the reactance |
| D. | Variable transformer |
| Answer» D. Variable transformer | |
| 349. |
The power factor of industrial loads is generally |
| A. | Unity |
| B. | Lagging |
| C. | Leading |
| D. | Zero |
| Answer» C. Leading | |
| 350. |
By which of the following methods string efficiency can be improved? |
| A. | Using a guard ring |
| B. | Grading the insulator |
| C. | Using long cross arm |
| D. | Any of the above |
| Answer» E. | |