PSPCL-JE’21 EE: Daily Practices Quiz 12-Oct-2021

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PSPCL RECRUITMENT 2021

Punjab State Power Corporation Ltd. (PSPCL), a power generating and distributing company of the Government of Punjab state, has released the notification for recruitment to the post of Clerk, Revenue Accountant, Junior Engineer (Electrical), Assistant Lineman & Assistant Sub Station Attendant Posts.
A total of 75 vacancies have been announced for the recruitment process of JE ELECTRICAL Engineering.

Exam Dates: 10 N0V-21 to 17 Nov-21

PSPCL-JE’21 EE: Daily Quiz

PSPCL-JE’21 EE: Daily Practices Quiz 12-Oct-2021

Each question carries 1 mark.
Negative marking: 1/4 mark
Total Questions: 06
Time: 06 min.

Q1. An IGBT is a combination of…
(a) SCR and MOSFET
(b) UJT and MOSFET
(c) BJT and MOSFET
(d) None of the above

Q2. The steepness of a traveling wave is attenuated by:
(a) Line resistance
(b) Line capacitance
(c) Line inductance
(d) Both b and c

Q3. Skewing is done in…….part of induction motor.
(a) Pole shoe
(b) Conductor
(c) Stator
(d) Rotor bar

Q4. In an R-L series circuit, the phase difference ϕ between applied voltage and circuit
current will increase if …….
(a) XL is increased
(b) R is increased
(c) XL is decreased
(d) supply frequency is decreased

Q5. A coil takes apparent and reactive powers of 100 VA and 80 VAR respectively. The
Q factor of the coil is ……
(a) 1.33
(b) 8
(c) 10
(d) None of the above

Q6. For a generating station. The diversity factor is always:
(a) Less than one
(b) Greater than one
(c) Equal to zero
(d) None of the given options

SOLUTIONS

S1. Ans.(c)
Sol. An IGBT is a combination of BJT and MOSFET.
IGBT is a bipolar device.
It has a high switching frequency.
Low conduction loss.

S2. Ans.(a)
Sol. Attenuation is defined as the loss of signal strength when it travels. The steepness of a traveling wave can be reduced by either increasing the wavelength or reducing the amplitude. When the traveling wave passes through a resistor, there will be energy loss of the wave, while it travels through the resistor in the form of heat. Thus, the steepness of the traveling waves is attenuated by the resistance of the line.

S3. Ans.(d)
Sol. Skewing is done in the rotor bar part of the induction motor to prevent cogging.
NOTE: The phenomenon of Magnetic Locking between the stator and the rotor teeth is called Cogging or Teeth Locking.

S4. Ans.(a)
Sol. In an R-L series circuit, the phase difference ϕ between applied voltage and circuit current will increase if X_L is increased.
Phase angle ϕ=tan^(-1)⁡(ωL/R)
Phase angle for series R-L circuit increases if…
XL is increased.
R is the decreased
frequency(f) is increased.

S5. Ans.(a)
Sol. Q factor = (Reactive power)/(Active power)=80/√(100^2-80²)=80/60=1.33 .

S6. Ans.(b)
Sol. for a generating station, the diversity factor is always > 1.
Diversity factor = ((sum of individual max demand))/((coeicident max.demand of whole system) )