2019 SSC Junior Engineer Electrical Online Exam 2019 CPWD/CWC/MES Electrical Engineering Set 1.1

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1. Which of the following is the function of the moderator in a nuclear reactor ?




... Answer is B)
function of the moderator in a nuclear reactor.Controlling chain reaction
The moderator of a nuclear reactor is a substance that slows neutrons down.
In traditional nuclear reactors, the moderator is the same thing as the coolant: it's water! When fast neutrons strike the hydrogen atoms in H2O, they slow down a lot
(like a billiard ball striking another). .

2. The laws involved in the expression e= -dΦ/dt are ?




... Answer is C)
Faraday's law states that a current will be induced in a conductor which is exposed to a changing magnetic field
while lenz's law states that the direction of this induced current will be such that the magnetic field created by induced current opposes the initial changing magnetic field which produced it.


3. In the full-wave rectifier circuit in the figure, the diodes that conduct when positive have wave of AC signal applied are- ?




... Answer is A)
During positive half cycle D1 will be forward basied D4 will be reverse bias hence only D1 conductor
while during return path D2 will be forward bias & provide a conductive path to complete the circuit.


4. In the two wattmeter method, the readings of the two wattmeter are 500 W, 500 W respectively. The load power factor ?




... Answer is D)


5. Identify the INCORRECT statement with regards to synchronous motors ?




... Answer is B)
The synchronous motors are doubly excited. One is 3 phase supply given to stator and other is DC excitation given to rotor of the motor.
The 3 phase AC to stator produces Rotating Magnetic Field (RMF) in the air gap, this rotates at Synchronous Speed Ns given as
Ns= (120*f)/P
The DC is given to rotor, which produces fixed magnetic poles.
when supply is given to stator starts rotating and stator poles too rotate at synchrocous speed.
these poles interchange their position due to alternating nature of current .
the rotor cannot pick up the quick reversal of stator.
due to this clockwise and counterclockwise directions of torque will develop making average torque zero .


6. A single phase circuit's power factor can be measured with a ?




... Answer is D)
A single phase circuit power factor can be measured with a combination of a voltmeter Ammeter and wattmeter

The power factor in a single-phase circuit (or balanced three-phase circuit) can be measured with the wattmeter-ammeter-voltmeter method, where the power in watts is divided by the product of measured voltage and current.


7. Find the net capacitance of the combination in which 10 capacitors of 10µF are connected in parallel ?




... Answer is D)


8. Extension of moving iron ammeter range can be done by using ?




... Answer is C)
Shunts: The range of an ammeter can be extended by connecting a low resistance, called shunt, connected in parallel with ammeter.

9. Annual load factor of a generation station is equal to ?




... Answer is C)
Load factor always less then 1

10. _ opposes the change in circuit voltage. ?




... Answer is B)
A capacitor opposes changes in voltage. If you increase the voltage across a capacitor, it responds by drawing current as it charges. ... If you drop the voltage across a capacitor, it releases it's stored charge as current.







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