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# DFCCIL’21 EE: Daily Practice Quiz. 16-Sep-2021

## DFCCIL Recruitment 2021

Dedicated Freight Corridor Corporation of India Limited (DFCCIL) Public Sector Undertaking under the administrative control of the Government of India (Ministry of Railways).DFCCIL has released the official notification for the recruitment of 1074 vacancies for the recruitment of Junior Executives, Executives, and Junior Managers through their official website, i.e. dfccil.com.

## EXAM DATES

26 SEPT TO 30 SEPT

## DFCCIL’21 EE: Daily Practices Quiz

DFCCIL’21 EE: Daily Practices Quiz 16-Sep-2021

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

Q1. Phase reversed of 180⁰ as compared to input occurs in the output of
(a) CE amplifier
(b) CB amplifier
(c) CC amplifier
(d) All of the above

Q2. Which of the following is/are represents lag compensator?
(a) (s+2)/(s+1)
(b) (s+2)/(s+5)
(c) Both a & b
(d) None of the above

Q3. A Potentiometer is basically a
(a) Deflection type instrument
(b) Null type instrument
(c) A digital instrument
(d) Both a and b

Q4. Which damping is used in moving iron instrument?
(a) Air friction damping
(b) Eddy current damping
(c) Fluid friction damping
(d) Electromagnetic damping

Q5. The Eddy current loss is proportional to the
(a) Frequency
(b) Square of the frequency
(c) Cube of the frequency
(d)Square root of the frequency

Q6. Voltage regulation of a transmission line should be ________
(a) Minimum
(b) Maximum
(c) Greater than 50 %
(d) Less than 50 %

## SOLUTIONS

SOLUTIONS
S1. Ans.(a)
Sol. Phase reversed of 180⁰ as compared to input occurs in the output of CE amplifier.

S2. Ans.(a)
Sol. transfer function for phase lag compensator will be
G(s)=((1+Ts))/((1+βTs))
Where, β>1.
For phase lag compensator, pole will be near to origin.
Hence, option (a) is right.

S3. Ans.(b)
Sol. A potentiometer is a null type instrument because the reading of the unknown voltage is measured when the current flowing through the galvanometer is zero (I_g=0).

S4. Ans.(a)
Sol. In moving iron instrument the damping used is Air friction damping, by a vane moving in a sector shaped chamber.
NOTE:
The moving iron instrument uses the air friction damping while the moving coil instrument uses the eddy current damping system.

S5. Ans.(b)
Sol. Eddy current loss in a transformer is fixed, and it depends on the core material’s magnetic properties. Eddy current loss is given as:
Pe=Ke Bm^2 f^2 t^2 V watts

S6. Ans.(a)
Sol. More value of voltage regulation means more voltage fluctuations and this is undesirable. So, the value of voltage regulation should be as low as possible.

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