Control Systems Expected MCQ PDF 2 For Coal India Limited (CIL) MT Exam 2017

1)   Which among the following controls the speed of D.C. motor?

a. Galvanometer
b. Gauss meter
c. Potentiometer
d. Tachometer

ANSWER: Tachometer

2)   Into which
energy signal does the position sensor convert the measured position of
servomotor in servomechanisms?

a. Mechanical
b. Electrical
c. Thermal
d. Light

ANSWER: Electrical

3)   What is the value of steady state error in closed loop control systems?

a. Zero
b. Unity
c. Infinity
d. Unpredictable


4)   A good control system should be sensitive to __________

a. Internal disturbances
b. Environmental parameters
c. Parametric variations
d. Input signals (except noise)

ANSWER: Input signals (except noise)

5)   For the transfer function given below, where does the zero of the system lie?
G(s) = 5s -1 / s2 + 5s + 4

a. s = -1 & s = -1/4
b. s = -4 & s = -1
c. s = 1/5
d. s = -1/5

ANSWER: s = 1/5

6)   If a signal is passed through an integrator, it _____the amplitude of noise signal.

a. Enhances
b. Reduces
c. Stabilizes
d. Factorizes

ANSWER: Reduces

7)   Laplace transform of an impulse response is regarded as _____function of the system

a. Analytic
b. Parabolic
c. Transfer
d. Hypothetical

ANSWER: Transfer

8)   The fundamental function of a tachometer is the conversion of angular _______ into voltage

a. Velocity
b. Displacement
c. Acceleration
d. Current

ANSWER: Velocity

9)   If finite
number of blocks are connected in series or cascade configuration, then
how are the blocks combined algebraically?

a. By addition
b. By multiplication
c. By differentiation
d. By integration

ANSWER: By multiplication

10)   Associative
law for summing point is applicable only to those summing points which
are __________connected to each other.

a. Directly
b. Indirectly
c. Orthogonally
d. Diagonally

ANSWER: Directly

11)   For the elimination of feedback loops, the derivation based on transfer function of ______ loop is used.

a. Open
b. Closed
c. Both a and b
d. None of the above

ANSWER: Closed

12)   In block diagram representation, what do the lines connecting the blocks, known as?

a. Branches
b. Nodes
c. Datums
d. Sources

ANSWER: Branches

13)   In a signal flow graph method, how is an overall transfer function of a system obtained?

a. Poisson’s equation
b. Block diagram reduction rules
c. Mason’s equation
d. Lagrange’s equation

ANSWER: Mason’s equation

14)   While
solving signal flow graph using Mason’s gain equation, what does the
second letter in two subscript notation of ‘L’ stand for?

a. Serial number of loop
b. Parallel number of loop
c. Number of touching loops
d. Number of non-touching loops

ANSWER: Number of non-touching loops

15)   For which systems are the signal flow graphs applicable?

a. Causal
b. Invertible
c. Linear time invariant system
d. Dynamic

ANSWER: Linear time invariant system

16)   Two loops are said to be non-touching only if no common ______exists between them.

a. Loop
b. Feedback path
c. Branch
d. Node


17)   In time domain system, which response has its existence even after an extinction of transient response?

a. Step response
b. Impulse response
c. Steady state response
d. All of the above

ANSWER: Steady state response

18)   Which among the following is represented by a parabolic input signal?

a. Position
b. Force
c. Velocity
d. Acceleration

ANSWER: Acceleration

19)   Type 0 systems are unsuitable ___________

a. For ramp inputs
b. If the input is parabolic in nature
c. Both a and b
d. None of the above

ANSWER: Both a and b

20)   If a type 0 system is subjected to step input, what is its effect on steady state error?

a. It increases continuously
b. It remains constant
c. It decreases monotonically
d. It gets subjected to another input

ANSWER: It remains constant

21)   Consider
that the pole is located at origin and its laplace representation is
1/s. What would be the nature of pole response?

a. Rising exponential
b. Decaying exponential
c. Sinusoidal
d. Constant value

ANSWER: Constant value

22)   In
accordance to relative stability, the settling time exhibits inversely
proportional nature to ________parts of roots

a. Real positive
b. Real negative
c. Imaginary positive
d. Imaginary negative

ANSWER: Real negative

23)   In Routh array, if zero is found in the first column, then by which term it needs to be replaced?

a. δ
b. η
c. σ
d. ε


24)   In a second
order system, if the damping ratio is greater than equal to ‘1’, then
what would be the nature of roots?

a. Imaginary
b. Real and equal
c. Real but not equal
d. Complex conjugate

ANSWER: Real but not equal

25)   For drawing
root locus, the angle of asymptote yields the direction along which
_________branches approach to infinity.

a. p + z
b. p – z
c. p / z
d. p x z

ANSWER: p – z

26)   Which point on root locus specifies the meeting or collision of two poles?

a. Centroid
b. Break away point
c. Stability point
d. Anti-break point

ANSWER: Break away point

27)   What should be the nature of root locus about the real axis?

a. Assymetric
b. Symmetric
c. Exponential
d. Decaying

ANSWER: Symmetric

28)   If the
system is specified by open loop transfer function G(s)H(s) = k / s(s+3)
(s + 2), how many root loci proceed to end at infinity?

a. 2
b. 3
c. 5
d. 6


29)   Which plots
in frequency domain represent the two separate plots of magnitude and
phase against frequency in logarithmic value?

a. Polar plots
b. Bode plots
c. Nyquist plots
d. All of the above

ANSWER: Bode plots

30)   How is the sinusoidal transfer function obtained from the system transfer function in frequency domain?

a. Replacement of ‘jω’ by ‘s’
b. Replacement of ‘s’ by ‘ω’
c. Replacement of ‘s’ by ‘jω’
d. Replacement of ‘ω’ by ‘s’

ANSWER: Replacement of ‘s’ by ‘jω’

31)   According to
the principle of log-scales, if the ratio between two points is same,
then the two points get ________equally.

a. United
b. Separated
c. Multiplexed
d. Mixed

ANSWER: Separated

32)   If a pole is located at origin, how does it get represented on the magnitude plot?

a. -10 log (ω) dB
b. -20 log (ω) dB
c. -40 log (ω) dB
d. -60 log (ω) dB

ANSWER: -20 log (ω) dB

33)   Due to an addition of pole at origin, the polar plot gets shifted by ___ at ω = 0?

a. -45°
b. -60°
c. -90°
d. -180°

ANSWER: -90°

34)   Consider the system represented by the equation given below. What would be the total phase value at ω = 0?
200/ [s3 (s + 3) (s + 6) (s + 10)]

a. -90°
b. -180°
c. -270°
d. -360°

ANSWER: -270°

35)   Which among the following are the interconnected units of state diagram representation?

a. Scalars
b. Adders
c. Integrators
d. All of the above

ANSWER: All of the above

36)   Which among the following plays a crucial role in determining the state of dynamic system?

a. State variables
b. State vector
c. State space
d. State scalar

ANSWER: State variables

37)   In P-D controller, the derivative action plays a significant role in increasing _______ of response.

a. Time
b. Distance
c. Speed
d. Volume


38)   In addition to storage instructions, PLC controls __________

a. Logic sequence timing
b. Counting
c. Arithmetic operations
d. All of the above

ANSWER: All of the above

39)   Which is the
correct sequence of operational steps necessary for proper operation of
an elevator (lift) control mechanism?
1. Up switch
2. Stop switch
3. Down switch
4. Start switch

a. 1-2-3-4
b. 2-1-4-3
c. 4-2-1-3
d. 3-1-2-4

ANSWER: 4-2-1-3

40)   How many digital inputs are present in PLCs?

a. 4
b. 8
c. 16
d. 32


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