1) Which system exhibits the initiation of corrective action only after the output gets affected?
a. Feed forward
b. Feedback
c. Both a and b
d. None of the above
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2) What should be the nature of bandwidth for a good control system?
a. Large
b. Small
c. Medium
d. All of the above
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3) If an impulse response of a system is e-5t, what would be its transfer function?
a. 1/ s - 5
b. 1/ s + 5
c. (s+1) / (s+5)
d. (s2 - 5s)/ (s-5)
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4) Which among the following are the elements of rotational motion?
a. Mass, Spring, Friction
b. Inertia, Damper, Spring
c. Work, Energy, Power
d. Force, Pressure, Viscocity
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5) Match the following notations with their meanings:
A. G(s) ---------- 1) Laplace of error signal
B. H(s) ---------- 2) Laplace of output signal
C. C(s) ---------- 3) Forward transfer function
D. E(s) ---------- 4) Feedback transfer function
a. A- 2, B- 3, C- 1, D- 4
b. A- 3, B- 4, C- 2, D- 1
c. A- 2, B- 3, C- 4, D- 1
d. A- 1, B- 2, C- 3, D- 4
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6) At summing point, more than one signal can be added or _________
a. Subtracted
b. Multiplied
c. Both a and b
d. None of the above
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7) The value of variables at each node is _________the algebraic sum of all signals arriving at that node.
a. Less than
b. Equal to
c. Greater than
d. None of the above
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8) In signal flow graph, the product of all ______gains while going through a forward path is known as 'Path gain'.
a. Branch
b. Path
c. Node
d. Loop
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9) If a type 1 system is subjected to parabolic input, what will be the value of steady state error?
a. 0
b. 100
c. Constant k
d. Infinite
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10) On which factor does the steady state error of the system depend?
a. Order
b. Type
c. Size
d. Prototype
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11) Consider the equation S3 + 3s2 + 5s + 2 = 0. How many roots are located in left half of s-plane?
a. Zero
b. Two
c. Three
d. Four
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12) If the system is represented by characteristic equation s6 + s4 + s3 + s2 + s + 3 = 0, then the system is_________
a. Stable
b. Unstable
c. Marginally stable
d. Unpredictable
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13) If poles are added to the system, where will the system tend to shift the root locus?
a. To the left of an imaginary axis
b. To the right of an imaginary axis
c. At the center
d. No shifting takes place
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14) For a unity feedback system with G(s) = 10 / s2, what would be the value of centroid?
a. 0
b. 2
c. 5
d. 10
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15) If 'ξ' approaches to zero, the peak resonance would ________
a. Also be zero
b. Be unity
c. Tend to infinity
d. Become equal to peak overshoot
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16) At which condition of 'ξ', resonant peak does not exist and its maximum value is considered to be unity along with zero resonant frequency?
a. 0 < ξ < 0.707
b. ξ > 0.707
c. ξ = 0
d. ξ = 1
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17) If the damping of the system becomes equal to zero, which condition of the resonant frequency is likely to occur?
a. ωr = ωd
b. ωr > ωn
c. ωr < ωn
d. ωr = ωn
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18) If the resonant peak is estimated to be '5', which among the following would be the correct value of damping?
a. ξ = 0.3
b. ξ = 1
c. ξ = 3.2
d. ξ = 5.55
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19) If a system is said to have a damping ξ = 0.5532 with the natural frequency ωn = 2 rad/sec, what will be the value of resonant frequency (ωr)?
a. 1.2456 rad/s
b. 1.7352 rad/s
c. 2.3421 rad/s
d. 3.66 rad/s
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20) In frequency response, the resonance frequency is basically a measure of _______ of response.
a. Speed
b. Distance
c. Angle
d. Curvature
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21) The frequency at which the phase of the system acquires ____ is known as 'Phase crossover frequency'.
a. 90°
b. -90°
c. 180°
d. -180°
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22) At which frequency does the magnitude of the system becomes zero dB?
a. Resonant frequency
b. Cut-off frequency
c. Gain crossover frequency
d. Phase crossover frequency
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23) If the phase angle at gain crossover frequency is estimated to be -105°, what will be the value of phase margin of the system?
a. 23°
b. 45°
c. 60°
d. 75°
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24) The system is said to be marginally stable, if gain margin is ______
a. 0
b. 1
c. +∞
d. None of the above
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25) If the constant 'k' is positive, then what would be its contribution on the phase plot?
a. 0°
b. 45°
c. 90°
d. 180°
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26) If the unity feedback system is given by the open loop transfer function G(s) = ks2 / [(1 + 0.3s) (1+ 0.05s)], what would be the initial slope of magnitude plot?
a. 20 dB/decade
b. 40 dB/decade
c. 60 dB/decade
d. Unpredictable
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27) If the system is represented by G(s) H(s) = k (s+7) / s (s +3) (s + 2), what would be its magnitude at ω = ∞?
a. 0
b. ∞
c. 7/10
d. 21
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28) According to Nyquist stability criterion, where should be the position of all zeros of q(s) corresponding to s-plane?
a. On left half
b. At the center
c. On right half
d. Random
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29) Consider a feedback system with gain margin of about 30. At what point does Nyquist plot crosses negative real axis?
a. -3
b. -0.3
c. -30
d. -0.03
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30) For Nyquist contour, the size of radius is _______
a. 25
b. 0
c. 1
d. ∞
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31) If a Nyquist plot of G (jω) H (jω) for a closed loop system passes through (-2, j0) point in GH plane, what would be the value of gain margin of the system in dB?
a. 0 dB
b. 2.0201 dB
c. 4 dB
d. 6.0205 dB
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32) Which principle specifies the relationship between enclosure of poles & zeros by s-plane contour and the encirclement of origin by q(s) plane contour?
a. Argument
b. Agreement
c. Assessment
d. Assortment
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33) Which among the following constitute the state model of a system in addition to state equations?
a. Input equations
b. Output equations
c. State trajectory
d. State vector
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34) State model representation is possible using _________
a. Physical variables
b. Phase variables
c. Canonical state variables
d. All of the above
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35) Which mechanism in control engineering implies an ability to measure the state by taking measurements at output?
a. Controllability
b. Observability
c. Differentiability
d. Adaptability
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36) According to the property of state transition method, e0 is equal to _____
a. I
b. A
c. e-At
d. -eAt
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37) Which among the following is a disadvantage of modern control theory?
a. Implementation of optimal design
b. Transfer function can also be defined for different initial conditions
c. Analysis of all systems take place
d. Necessity of computational work
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38) Which among the following is a unique model of a system?
a. Transfer function
b. State variable
c. Both a and b
d. None of the above
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39) Which architectural unit/block of PLC decides the sequence of different operations to be executed by means of instructions written in memory?
a. Memory
b. Programming software
c. I/O interface
d. CPU
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40) Which among the following units of PLC is adopted to convey the control plan to CPU?
a. Memory
b. Power supply unit
c. I/O interface
d. Programming software
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