SSC JE Electrical Important MCQ Part 15


SSC JE Electrical Important MCQ PDF Part 15

1.In lap winding of a DC generator, the number of parallel paths is equal to ___________

A.2
B.Number of poles
C.1
D.Number of Interpol’s

Answer  : B (Number of parallel paths (A) in case of lap winding is equal to the number poles (P) of the machine while a = 2 in case of wave winding)

2.In three phase transformer, negative voltage regulation occurs at ___________


A.Unity power factor
B.Lagging power factor
C.Rated KVA of transformer
D.Leading power factor

Answer  : D (Voltage regulation can be defined as the ratio of the difference in the secondary voltage from no load to the full load to the full load voltage.Negative voltage regulation means secondary voltage can increase when the transformer is loaded.This usually happens when there are excessive power factor correction capacitors (overcompensation) at the secondary side of the transformer or if the load has a leading power factor)

3.In railway electrification, the circuit breaker used is ______________

A.SF6 circuit breaker
B.Bulk oil circuit breaker
C.Airblast circuit breaker
D.Minimum oil circuit breaker

Answer  : C

4.Cables used for 220 kV lines are _________ insulated

A.Paper
B.Compressed oil
C.PVC
D.Mica

Answer  : B

5.PMMC voltmeter is an example for which type of instrument

A.Digital type
B.Indicating type
C.Recording type
D.Integrating type

Answer  : B (The instrument which indicates the magnitude of the measured quantity is known as the indicating instrument,Example- Ordinary voltmeters, ammeters and watt-meter’s)

6.Which one of the following laws deals with electrolysis

A.Faraday’s law
B.Joule’s law
C.Ohm’s law
D.Kirchhoff’s law

Answer  : A

7.In the 3 phase double squirrel cage induction motor, the outer cage is wound with bars having ______________,

A.low resistance and high inductance
B.high resistance and low reactance
C.high resistance and high inductance
D.low resistance and low inductance

Answer  : B (Outer cage has high resistance and low reactance whereas the inner cage has low resistance and high reactance)

8.____________ can be used to step up DC voltage

A.Inverter
B.Chopper
C.Snubber
D.Cyclo converter

Answer  : B

9.The unit of conductivity is _______________

A.mho/meter
B.ohm/sq.m
C.ohm/m
D.mho/sq.m

Answer  : A (The SI unit of conductivity is Siemens per meter (S/m) or mho/meter)

10.Power factor is given by ______________

A.Real power/Apparent power
B.Reactive power/Apparent power
C.Apparent power/Real power
D.Apparent power/Reactive power

Answer  : A (Power Factor = Real Power/Apparent Power, or p.f. = W/VA)

11.In delta connection if the line voltage is 1732 V then what will be the phase voltage

A.173.2 V
B.1000 V
C.1732 V
D.3000 V

Answer  : C (In delta connection line voltage = phase voltage)

12.In alternator winding, the numerical value of the pitch factor will always be ———-

A.equal to distribution factor
B.less than unity
C.more than unity
D.equal to unity

Answer  : B ( Pitch factor is the ratio of phasor sum of induced emfs per coil to the arithmetic sum of induced emfs per coil. Therefore, it must be less than unity)

13.The resistance of shunt field 500 V DC shunt generator is 200 ohms. What will be the field current

A.0 .8 Amps
B.10 Amps
C.2.5 Amps
D.7 Amps

Answer  : C (Field Current = 500 V/200 ohm = 2.5 Amps)

14.What is the SI unit of specific resistance

A.Ohm / metre
B.Ohm
C.Ohm-metre
D.Metre / ohm

Answer  : C (Unit for specific resistance is the ohm-meter (Ω-m), or ohm-centimeter (Ω-cm))

15.The difference of level between the points of support and the lower point of the conductor of a transmission line is ———–

A.Span
B.Clearance
C.Slag
D.Sag

Answer  : D

16.Which type of rotor is best suitable for medium and slow speed operation in synchronous motor ?

A.Salient pole rotor
B.Smooth cylindrical type rotor
C.Split ring rotor
D.Slip ring rotor

Answer  : A (Generally used in lower speed electrical machines,100 RPM to 1500 RPM)

17.______________ relay has the capability to detect a major fault in transformer.

A.Buchholz
B.Distance
C.Directional
D.Over current

Answer  : A

18.The value of the capacitive reactance of a capacitor when it is connected with AC supply will be ———-

A.inversely proportional to the supply frequency
B.directly proportional to the supply voltage
C.inversely proportional to the supply voltage
D.directly proportional to the supply frequency

Answer  : A (Xc=1/2πfC)

19.The unit of electric field intensity is ______________

A.Coulomb/m
B.Weber
C.Coulomb
D.Newton/Coulomb

Answer  : D (E = F/q,Unit is newtons per coulomb (N/C) or volts per meter (V/m))

20.The DC series motor should be connected with the load by means of ———-.

A.direct coupling drive
B.direct V belt drive
C.direct chain drive
D.direct flat belt drive

Answer  : A

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