Top 20 electrical subjects practice mcq

1➤ Which of the following is not an example of Vector quantity?

Electric field intensity AccelerationMassMagnetic field intensity

2➤ For series connected SCRS, static equalization is obtained with the help of

Resistors and capacitorsResistors, capacitors and diodesCapacitors only Resistors only

3➤ With reference to the divergence, which of the following statement is WRONG?

Divergence operation can be represented by del operatorExpressions for divergence in different co-ordinate systems are differentDivergence of a scalar has no meaningDivergence of a vector is a vector quantity

4➤ For a synchronous generator supplying a balanced 3-phase load, the armature in magnitude and rotates at reaction flux is speed.

Variable, Super-synchronousConstant, SynchronousConstant, Sub-synchronousVariable, Sub-synchronous

5➤ The law states that, "The line integral of magnetic field intensity ♬ around a closed path is exactly is equal to the direct current enclosed by the path."

Gauss's lawBiot-Savart lawAmpere's circuital lawPoisson's law

6➤ Which of the following characteristic is not desirable in measuring instrument?

AccuracyDriftRepeatabilityLinearity

7➤ Electrostatic type instruments are primarily used as

AmmetersVoltmeter OhmmeterWattmeters

8➤ The percentage voltage regulation of short transmission line if its sending end and reciving end voltages are 160 KV and 132 KV respectively is

0.30.21210.38220.1212

9➤ In case of variable head flow meters, velocity of flowing liquid is

Inversely proportional to cross-sectional area of pipe through which fluid is flowingDirectly proportional to density of the flowing liquidInversely proportional to density of the flowing liquidNone of the options

10➤ In armature core silicon steel is used to ________ and laminations are given to _____

rotate motor in clockwise direction , avoid anticlockwise rotationreduce noise, provide dampingRotate motor fast, avoid frictionreduce hysteresis loss, minimise eddy current loss

11➤ Line-synchronized UJT triggering circuit provides gate pulses ………………..

Randomly to SCRsSynchronized with reversed line voltage To turn-off all SCRs in the circuitSynchronized with applied line voltage

12➤ Star rating is a part of ---------Programme of BEE.

Demand side managementStandard and Labeling BLYNone of the options

13➤ The dynamometer type wattmeter can be used to measure

AC or DC power.AC power onlyAC power of single - phase circuitsDC power only

14➤ Which chopper circuits use saturable reactor?

Load commutatedAuxiliary commutatedMorgan chopper Jones chopper

15➤ If we observe the change in colour of silica gel in a breather of three phase transformer it.

internal winding inside the oil is short circuited.the oil inside the transformer tank contains small amount of moisturetransformer oil need replacementthe breather need replacement

16➤ IGBT device is a ………………

Frequency-controlled devicePower-controlled deviceVoltage-controlled device All of these

17➤ The efficiency of an induction motor is about

80-90%Less than 50%100%50-60%

18➤ Which of the following 3-phase ac to dc converter requires neutral point connection? .

3-phase semiconductor3-phase full converter3-pahse half wave converter3-phase converter with diodes

19➤ Which of the following is not covered by Customer domain in smart grid?

Electric vehiclesDistribution linesPremises networksSmart appliances

20➤ The use of …………. instruments are merely confined within laboratories as standardizing instruments.

RecordingAbsoluteIndicatingIntegrating

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