SSC JE Electrical Important MCQ Part 17
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Attempt Free SSC JE Electrical Important MCQ Part 17 Here. Read The Important SSC MCQ From Below.
SSC JE Electrical Important MCQ PDF Part 17
1.Equivalent capacitance seen at the terminals of the circuit in Fig. is
A.20 μF
B.40 μF
C.60 μF
D.30 μF
Answer : A
SSC JE Electrical Important MCQ Part 17
(The 20-μF and 5-μF capacitors are in series; their equivalent capacitance is=20×5/20+5== 4 μF
This 4-μF capacitor is in parallel with the 6-μF and 20-μF capacitors;their combined capacitance is 4 + 6 + 20 = 30 μF
This 30-μF capacitor is in series with the 60-μF capacitor. Hence, the equivalent capacitance for the entire circuit is
Ceq =30×60/30 + 60= 20 μF
2.Consider the circuit in Fig.Under dc conditions,The value of iL is
A.9 A
B.4 A
C.6 A
D.2 A
Answer : D
(Under dc conditions, we replace the capacitor with an open circuit and the inductor with a short circuit, as in Fig. below
i = iL =12/1 + 5= 2 A )
SSC JE Electrical Important MCQ Part 17
3.The equivalent inductance of the circuit shown in Fig is
A.42 H
B.6 H
C.18 H
D.10 H
Answer : C
(The 10-H, 12-H, and 20-H inductors are in series=10+12+20= 42 H
This 42-H inductor is in parallel with the 7-H inductor=7× 42/7 + 4== 6 H
This 6-H inductor is in series with the 4-H and 8-H inductors. Hence,Leq = 4 + 6 + 8 = 18 H)
4.A transistor has a collector current of 10 mA and a base current of 40 μA. What is the current gain of the transistor
A.250
B.300
C.360
D.280
Answer : A (Divide the collector current by the base current to get βdc=Ic/Ib=10 mA/40 μA=250)
SSC JE Electrical Important MCQ Part 17
5.What is the capacity of a battery which can deliver a current of 20 Amps continuously for 2 hours and 30 minutes
A.50 AH
B.46 AH
C.40 AH
D.60 AH
Answer : A (Battery Capacity= Amps * hours=20*150/60=50 AH)
6.The series field of a compound generator is wound with
A. few turns in thick wire
B. few turns in thin wire
C. more tuns in thick wire
D. more turns in thin wire
Answer : A (In a Compound Wound Generator, there are two sets of the field winding on each pole. One of them is connected in series having few turns of thick wire, and the other is connected in parallel having many turns of fine wire with the armature winding)
7.The unit of electric flux density is
A. Farad/meter
B. Coulomb/sq.meter
C. Coulomb
D. Weber/sq.meter
Answer : B (D=φ/A=Q/4πr²,The SI unit of electric flux is Coulomb per meter square.)
SSC JE Electrical Important MCQ Part 17
8.The full form of ELCB is
A. Earth live circuit breaker
B. Earth leakage current breaker
C. Earth leakage circuit breaker
D. Earth line current breaker
Answer : C
9.Which type of insulators are used on 132 kV transmission lines
A. Pin type
B. Pin and Shackle type
C. Disc type
D. Shackle type
Answer : C (The suspension insulator is called as Disc Insulator,Use for 11 kV to 765 kV)
10.What is the purpose of pole shoes in DC generator
A. Magnetize the poles and produce the magne tic flux
B. Provide the mechanical support to magnetic poles
C. Provide the low resistance path to eddy currents
D. Spread out the magnetic flux uniformly in the air gap
Answer : D
SSC JE Electrical Important MCQ Part 17
11.As per the IE rules, the maximum load on the light and fan sub-circuit should be restricted to
A.500 Watts
B.1000 Watts
C.650 Watts
D.800 Watts
Answer : D (As per Indian Standard Specification (I.S.S), each lighting sub-circuit must have ten number of points or 800 watt whichever is less)
12.What is the name of the power generating station which uses the potential energy of water
A. Hydro power station
B. Thermal power station
C. Atomic power station
D. Nuclear power station
Answer : A
13.If two inductors of 7mH and 3mH are connected in series across the 250V 50Hz AC supply then the total inductive reactance will be
A.31.42 Ohms
B.10 Ohms
C.21 Ohms
D.3.142 Ohms
Answer : D
SSC JE Electrical Important MCQ Part 17
(Total Reactance is given by X=X₁+X₂=ω(L₁+L₂)=2πf(L₁+L₂)=2×3.14×50(7mH+3mH)=3.14×100(10×10⁻³)=3.14)
14.Type of DC motor used in electrical traction is
A.DC Series motor
B.DC Cummulative compound motor
C.DC Cummulative long shunt motor
D. All of these
Answer : A ( The dc series motor develops high torque at start which is an essential requirement of traction service)
15.When the 3 phase power is measured by two wattmeter method, at what power factor, the readings of both wattmeter will be equal and positive
A. Unity
B.0.5 Lag
C .Zero Power
D Less than 0.5 Lag
Answer : A
(PF=unity, So φ= 0
W1= VLI Cos(30° – 0)= VLI Cos30°= 0.866 VLI
W2= VLI Cos(30° + 0) = VLI Cos30°= 0.866 VLI
Thus when the power factor of load is unity then both the wattmeter reads the same value)
SSC JE Electrical Important MCQ Part 17
16.The chopper circuit converts __________ voltage
A. Fixed DC to variable AC
B. Fixed AC to variable DC
C. Fixed AC to variable AC
D. Fixed DC to variable DC
Answer : D (A chopper is a device that converts fixed DC input to a variable DC output voltage directly)
17.The time required by an AC quantity to complete one cycle is
A. power factor
B. frequency
C. cycle/ sec
D period
Answer : D
18.In controlled rectifier ________ device is used
A. Diode
B.SCR
C. Snubber
D.TRIAC
Answer : B
SSC JE Electrical Important MCQ Part 17
19.For protection of three phase induction motor from single phasing, ________ is used.
A. Electromagnetic over load device
B. Air break circuit breaker
C. Air blast circuit breaker
D. Bucholtz relay
Answer : A (A single phasing fault on an Induction Motor will cause the current in the other two phases to rise. To prevent damage to the motor winding, an over current protection relay/Electromagnetic over load device is normally fitted in the motor starter circuit)
20.In single phase AC circuit with impedance Z and resistance R, power factor is given by
A.Z/R
B.R/Z
C. Cos(R/Z)
D. Sin(Z/R)
Answer : B
SSC JE Electrical Important MCQ Part 17
