1. What is the algebraic sum of the reference input and feedback?
Correct : A. error signal
2. Feedback control systems are referred to as closed loop systems.
Correct : A. true
3. Which principle does the linear system follow?
Correct : D. principle of superposition
4. control systems have unpredictable & non-repeatable.
Correct : D. stochastic
5. The pressure inside the furnace is measured by
Correct : A. gauge
6. On what difference does the pneumatic system works?
Correct : B. pressure
7. In a thermal system, the temperature of the medium is
Correct : D. uniform
8. How many parameters does process control refer to?
Correct : C. 5
9. What is the effect of feedback in the overall gain of the system?
Correct : B. decreases
10. In a temperature control system, what conversion in signal takes place?
Correct : B. analog to digital
11. Which of the following are the not characteristics of the closed loop systems?
Correct : D. it does not has the ability to control the system transient response
12. Which one of the following effect in the system is not caused by negative feedback?
Correct : C. increase in distortion
13. Which of the statement is correct with regard to the bandwidth of the control loop system:
Correct : A. in systems where the low frequency magnitude in 0 db on the bode diagram, the bandwidth is measured at the -3 db frequency
14. Which of the statements are the advantages of closed loop systems over the open loop system:
Correct : B. the transient response in closed loop system decays more quickly than in open loop system.
15. In control system excessive bandwidth is not employed because
Correct : A. noise is proportional to bandwidth
16. Feedback control system is basically
Correct : B. low pass filter
17. Which of the following will not decrease as a result of introduction of negative feedback?
Correct : B. bandwidth
18. As compared to the closed loop system, an open loop system is
Correct : A. more stable but less accurate
19. Open loop system is stable than closed loop system
Correct : A. more
20. For the gain feedback system, does not affect the system output if KG is :
Correct : D. very large
21. Determine the sensitivity of the overall transfer function for the system shown in the figure below, at w=1 rad/sec with respect to the feedback path transfer function.
Correct : B. -1.11
22. Primary purpose of using Feedback is :
Correct : A. to reduce the sensitivity of the system to parameter variations.
23. Which of the following is not the feature of modern control system?
Correct : D. no oscillation
24. The output of the feedback control system must be a function of:
Correct : D. input and feedback signal
25. The principle of homogeneity and superposition are applied to:
Correct : C. linear time variant systems
26. In continuous data systems:
Correct : B. data is necessarily a continuous function of time at all points in the system
27. A linear system at rest is subject to an input signal r(t)=1-e-t. The response of the system for t>0 is given by c(t)=1-e-2t. The transfer function of the system is:
Correct : C. 2(s+1)/(s+2)
28. A transfer function has two zeroes at infinity. Then the relation between the numerator(N) and the denominator degree(M) of the transfer function is:
Correct : B. n=m-2
29. When deriving the transfer function of a linear element
Correct : C. initial conditions are assumed to be zero but loading is taken into account
30. If the initial conditions for a system are inherently zero, what does it physically mean?
Correct : C. the system is at rest or no energy is stored in any of its part
31. A signal flow graph is the graphical representation of the relationships between the variables of set linear algebraic equations.
Correct : A. true
32. Use mason’s gain formula to find the transfer function of the given signal flow graph:
Correct : B. abdeg/1-(bc+ef)+bcef
33. Use mason’s gain formula to find the transfer function of the following signal flow graph:
Correct : B. acdfg+bcefg/1-cd-fg-cdfg
34. Loop which do not possess any common node are said to be loops.
Correct : C. non touching loops
35. Signal flow graphs:
Correct : A. they apply to linear systems
36. Signal flow graphs are reliable to find transfer function than block diagram reduction technique.
Correct : A. true
37. The relationship between an input and output variable of a signal flow graph is given by the net gain between the input and output node is known as the overall
Correct : A. overall gain of the system
38. Use mason’s gain formula to calculate the transfer function of given figure:
Correct : B. g1+g2/1+g1h
39. Use mason’s gain formula to find the transfer function of the given figure:
Correct : C. g1+g2/1+g1h+g2h
40. Regenerative feedback implies feedback with
Correct : D. positive sign
41. The output of a feedback control system must be a function of
Correct : D. output and feedback signal
42. A control system with excessive noise, is likely to suffer from
Correct : A. saturation in amplifying stages
43. Zero initial condition for a system means
Correct : D. system is at rest and no energy is stored in any of its components
44. Transfer function of a system is used to calculate which of the following?
Correct : C. the output for any given input
45. The band width, in a feedback amplifier.
Correct : C. increases by the same amount as the gain decrease
46. On which of the following factors does the sensitivity of a closed loop system to gain changes and load disturbances depend?
Correct : D. all of the mentioned
47. The transient response, with feedback system,
Correct : D. decays quickly
48. The second derivative input signals modify which of the following?
Correct : D. the time constant and suppress the oscillations
49. The transient response, yt(t), of a system becomes as t tends to infinity.
Correct : A. 0
50. Delay time is the time required by a system to reach a quarter of its steady state value.
Correct : B. false
51. For non-unity feedback system, the error is calculated with respect to the reference signal.
Correct : B. false
52. Which of the following command will reveal the damping ratio of the system?
Correct : A. damp()
53. If the damping factor is zero, the unit-step response is
Correct : A. purely sinusoidal
54. If the damping ratio is equal to 1, a second-order system is
Correct : D. critically damped with equal roots
55. From the following graphs of the generalized transfer function 1/s+a, which plot shows a transfer function with a bigger value of a?
Correct : D. purple plot
56. From the following graphs of the generalized transfer function 1/as2, which plot shows the transfer function for a higher a?
Correct : D. purple
57. If the damping factor is less than the damping factor at critical damping, the time response of the system is
Correct : A. underdamped
58. This makes the system underdamped since the response of the system becomes a decaying sinusoid in nature.
Correct : D. 36/(s2+2s+36)
59. The system in originally critically damped if the gain is doubled the system will be :
Correct : C. under damped
60. Let c(t) be the unit step response of a system with transfer function K(s+a)/(s+K). If c(0+) = 2 and c(∞) = 10, then the values of a and K are respectively.
Correct : C. 10 and 2
61. The damping ratio and peak overshoot are measures of:
Correct : B. speed of response
62. A system has a complex conjugate root pair of multiplicity two or more in its characteristic equation. The impulse response of the system will be:
Correct : C. a sinusoidal oscillation which rises exponentially ; the system is therefore unstable
63. The step response of the system is c(t) = 10+8e-t-4/8e-2t . The gain in time constant form of transfer function will be:
Correct : D. -7.5
64. The steady state error for a unity feedback system for the input r(t) = Rt^2/2 to the system G(s) = K(s+2)/s(s3+7s2+12s) is
Correct : B. 6r/k
65. Find the velocity error constant of the system given below :
Correct : C. 4
66. Consider the unity feedback system with open loop transfer function the minimum value of the steady state error to a ramp input r(t) = 6tu(t) is OLTF = K/s(s+1)(s+2)
Correct : B. 2
67. A ramp input applied to a unity feedback system results in 5% steady state error. The type number and zero frequency gain of the system are respectively
Correct : A. 1 and 20
68. A particular control system yielded a steady state error of 0.20 for unit step input. A unit integrator is cascaded to this system and unit ramp input is applied to this modified system. What is the value of steady- state error for this modified system?
Correct : D. 0.25
69. The error constants described are the ability to reduce the steady state errors.
Correct : A. true
70. Systems of type higher than 2 are not employed in practice.
Correct : A. true
71. Steady state refers to
Correct : A. error at the steady state
72. The disadvantages of the error constants are:
Correct : C. they do not give information of the steady state error and fail to indicate the exact manner in which the error function change with time
73. The input of a controller is
Correct : B. error signal
74. Phase lag controller:
Correct : B. reduction in steady state error
75. Addition of zero at origin:
Correct : A. improvement in transient response
76. Derivative output compensation:
Correct : C. reduction is settling time
77. Derivative error compensation:
Correct : D. increase in damping constant
78. Lag compensation leads to:
Correct : B. attenuation
79. Lead compensation leads to:
Correct : A. increases bandwidth
80. Lag-lead compensation is a:
Correct : D. second order
81. Rate compensation :
Correct : C. increases damping factor
82. Negative exponential term in the equation of the transfer function causes the transportation lag.
Correct : A. true
83. Scientist Bode have contribution in :
Correct : A. asymptotic plots
84. Scientist Evans have contribution in :
Correct : C. root locus technique
85. Scientist Nyquist have contribution in:
Correct : B. polar plots
86. Which one of the following methods can determine the closed loop system resonance frequency operation?
Correct : D. m and n circle
87. If the gain of the open loop system is doubled, the gain of the system is :
Correct : A. not affected
88. Constant M- loci:
Correct : D. circles of constant phase shift for the closed loop transfer function
89. Constant N-loci:
Correct : C. circles of constant gain for the closed loop transfer function
90. Nichol’s chart:
Correct : B. plot of loop gain with the variation in frequency
91. For a stable closed loop system, the gain at phase crossover frequency should always be:
Correct : D. > 0 db
92. Which principle specifies the relationship between enclosure of poles & zeros by s- plane contour and the encirclement of origin by q(s) plane contour?
Correct : A. argument
93. 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?
Correct : D. 6.0205 db
94. For Nyquist contour, the size of radius is
Correct : D. ∞
95. According to Nyquist stability criterion, where should be the position of all zeros of q(s) corresponding to s-plane?
Correct : A. on left half
96. 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 = ∞?
Correct : A. 0
97. Consider the system represented by the equation given below. What would be the total phase value at ω = 0?
Correct : C. -270°
98. In polar plots, if a pole is added at the origin, what would be the value of the magnitude at Ω = 0?
Correct : B. infinity
99. In polar plots, what does each and every point represent w.r.t magnitude and angle?
Correct : C. phasor
100. A system has poles at 0.01 Hz, 1 Hz and 80Hz, zeroes at 5Hz, 100Hz and 200Hz. The approximate phase of the system response at 20 Hz is :