MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 283 Mcqs, each offering curated multiple-choice questions to sharpen your Control Systems knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
The performance specifications for a unity feedback control system having an open-loop transfer function G(s) = Kares(s + 1)(s + 2)(i) Velocity error coefficient KV > 10 sec 1 (ii) Stable closed-loop operation. The value of K, satisfying the above specifications, is |
| A. | K > 6 |
| B. | 6 < K < 10 |
| C. | K > 10 |
| D. | K > 20 |
| Answer» E. | |
| 52. |
A linear stable invariant system is forced with an input given below x (t) = A sin t x (t) [G (s) ] y (t) Under steady-state conditions, the output y (t) of the system will be |
| A. | A sin ( t + ), where = tan |
| B. | |G (j )| |
| C. | | G (j ) | A sin [ t + < G (j )] |
| D. | | G (j ) | A sin [2 t + < G (j )] |
| E. | AG (j ) sin [ t + G (j )] |
| Answer» C. | G (j ) | A sin [ t + < G (j )] | |
| 53. |
The asymptotic approximation of the log-magnitude versus frequency plot of a minimum phase system with real poles and one zero is shown in figure. Its transfer function is |
| A. | |
| B. | |
| Answer» E. | |
| 54. |
The transfer function of a compensating network is of the form 1 + Ts1 + TsIf this is a phase-lag network, the value of should be |
| A. | exactly equal to 0 |
| B. | between 0 and 1 |
| C. | exactly equal to 1 |
| D. | greater than 1 |
| Answer» C. exactly equal to 1 | |
| 55. |
The transfer function C/ R of the system shown in the figure is |
| A. | |
| B. | |
| Answer» C. | |
| 56. |
The open-loop transfer function of a system is given by G(s) H(s) = K(s + 1)(s + 3)s2 + 4s + 8Its root locus diagram is |
| A. | Fig:- A |
| B. | Fig:- B |
| C. | Fig:- C |
| D. | Fig:- D |
| Answer» B. Fig:- B | |
| 57. |
A unity feedback system has the open-loop transfer function G(s) = 1(s 1)(s + 2)(s + 3)The Nyquist plot of G(s) encircles the origin |
| A. | never |
| B. | once |
| C. | twice |
| D. | thrice |
| Answer» C. twice | |
| 58. |
A unity feedback system has an open-loop transfer function of the from KG(s) = K(s + a); b > as2(s + b)Which of the loci system in figure can be a valid root-loci for the system? |
| A. | Fig:- A |
| B. | Fig:- B |
| C. | Fig:- C |
| D. | Fig:- D |
| Answer» B. Fig:- B | |
| 59. |
The characteristic equation of a closed loop system is given by s4 + 6s3 + 11s2 + 6s + K = 0 Stable closed loop behaviour can be ensured when gain K is such that |
| A. | 0 < K < 10 |
| B. | K > 10 |
| C. | K < |
| D. | 0 < K 20 |
| Answer» B. K > 10 | |
| 60. |
For a standard feedback control loop, the sensitivity of the closed-loop transfer function T to forward path gain G and feedback path gain H are SGTSHTA. -1/(1 + GH)-1(1 + GH)B. -GH/(1 + GH)-H/(1 + GH)C. G/(1 + GH)1/(1 + GH)D. 1/(1 + GH)-GH/(1 +GH) |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 61. |
The system with transfer function Ks2(1 + sT)is operated in closed-loop with unity feedback. The closed-loop system is |
| A. | stable |
| B. | unstable |
| C. | marginally stable |
| D. | conditionally stable |
| Answer» C. marginally stable | |
| 62. |
The transfer function G (s) is Ks2(1 + sT). This open-loop system will be |
| A. | stable |
| B. | unstable |
| C. | marginally stable |
| D. | conditionally stable |
| Answer» B. unstable | |
| 63. |
Consider the following statements with reference to the block diagram of a control system given in the figure 1. For G2 = 0, the system is open-loop. 2. For G1 = 0, the system is closed-loop. 3. For G2 = H = 1, the system is closed-loop Of these statements |
| A. | 1, 2 and 3 are correct |
| B. | 1 and 2 are correct |
| C. | 2 and 3 are correct |
| D. | 1 and 3 are correct |
| Answer» D. 1 and 3 are correct | |
| 64. |
The unit impulse response of a system is given by C (t) = 0.5 e t/2. Its transfer function is |
| A. | 1/(s + 2) |
| B. | 1/(1 + 2s) |
| C. | 2/(1 + 2s) |
| D. | 2/(s + 2) |
| Answer» C. 2/(1 + 2s) | |
| 65. |
The open-loop transfer function of a unity negative feed back control system is given by G(s) = K(s + 2)(s + 1)(s - 7)the stability of the open-loop and closed-loop configuration of the system are respectively |
| A. | stable and stable |
| B. | unstable and stable |
| C. | stable and unstable |
| D. | unstable and unstable |
| Answer» C. stable and unstable | |
| 66. |
If the open-loop transfer function of the system is G(s) H(s) = K(s + 10)s(s + 8) (s + 16) (s + 72)then a closed loop pole will be located at s = 14, when the value of K is |
| A. | 4355 |
| B. | 2436 |
| C. | 9600 |
| D. | 2463 |
| Answer» C. 9600 | |
| 67. |
In the root-locus for open-loop transfer function G (s)H (s) = K(s + 6)(s + 3) (s + 5) the break away and break-in' points are located respectively at |
| A. | 2 and 1 |
| B. | 2.47 and 4.42 |
| C. | 7.58 and 7.23 |
| D. | 4.42 and 7.58 |
| Answer» E. | |
| 68. |
The close-loop transfer function of a control system is given by C(s) = 1 R(s)1 + s For the input r (t) = sin t, the steady state value of C(t) is equal to |
| A. | |
| B. | 1 |
| C. | |
| Answer» E. | |
| 69. |
For a unit step input, a system with forward path transfer function G(s) = 20/s2 and feedback path transfer function H(s) = (s + 5) has a steady state output of |
| A. | 20 |
| B. | 5 |
| C. | 0.2 |
| D. | zero |
| Answer» E. | |
| 70. |
The error response of a second order system to a step input is obtained as E (t) = 1.66 e 8t sin (6t + 37 ). The damping ratio is |
| A. | 0.4 |
| B. | 0.5 |
| C. | 0.8 |
| D. | 1.0 |
| Answer» D. 1.0 | |
| 71. |
The open loop transfer function of a unity feedback control system is given by G (s) = K(s + 2)s(s2 + 2s + 2)The centroid and angles of root locus asymptotes are respectively |
| A. | zero and + 90 , 90 |
| B. | 2/3 and + 60 , 60 |
| C. | zero and + 120 , 120 |
| D. | 2/3 and 90 and 90 , + 90 |
| Answer» B. 2/3 and + 60 , 60 | |
| 72. |
The Laplace transform of the function i(t) is I (s) = 10s + 4s(s + 1)(s2 + 4s + 5)Its final value will be |
| A. | 4/5 |
| B. | 5/4 |
| C. | 4 |
| D. | 5 |
| Answer» B. 5/4 | |
| 73. |
A linear discrete-time system has the characteristic equation, z3 0.81z = 0 The system |
| A. | is stable |
| B. | is marginally stable |
| C. | is unstable |
| D. | stability cannot be assessed from the given information. |
| Answer» B. is marginally stable | |
| 74. |
A lag compensation network (i) increases the gain of the original network without affecting stability (ii) reduces the steady state error (iii) reduces the speed of response (iv) permits the increase of gain if phase margin is acceptable. In the above, correct statements are |
| A. | All |
| B. | (i) and (ii) |
| C. | (ii), (iii) and (iv) |
| D. | (iii) and (ii) |
| Answer» B. (i) and (ii) | |
| 75. |
Consider a feedback control system with loop transfer function G(s) H(s) = K(1 + 0 5s)s(1 + s) (1 + 2s)The type of the closed loop system is |
| A. | zero |
| B. | one |
| C. | two |
| D. | three |
| Answer» C. two | |
| 76. |
The open-loop transfer function of the given Bode plot is |
| A. | |
| B. | |
| Answer» B. | |
| 77. |
The transfer function of a linear system is the |
| A. | ratio of the output V |
| B. | 1 (t) |
| C. | ratio of the derivatives of the output and the input. |
| D. | ratio of the Laplace transform of the output and that of the input with all initial conditions zeros. |
| E. | None of these |
| Answer» D. ratio of the Laplace transform of the output and that of the input with all initial conditions zeros. | |
| 78. |
A second order system is given as G(s) = K(1 + 1s) (1 + 2s) If the gain K is increased, then the phase margin |
| A. | gets increased |
| B. | gets decreased |
| C. | is unaffected |
| D. | gets decreased and becomes stable |
| Answer» C. is unaffected | |
| 79. |
G (s) =1s(1 + 6s)the system is |
| A. | stable |
| B. | unstable |
| C. | marginally stable |
| D. | conditionally stable |
| Answer» D. conditionally stable | |
| 80. |
In the following, pick out the linear systems. (i)d2y(t)+ a1dy(t)+ a2y(t) = u(t)dt2dt (ii) ydy(t)+ a1y(t)= a2u(t)dt (iii) 2d2y+ tdy+ t2y(t) =5dt2dt |
| A. | (i) and (ii) |
| B. | (i) only |
| C. | (i) and (iii) |
| D. | (ii) and (iii) |
| Answer» D. (ii) and (iii) | |
| 81. |
The log-magnitude plot of a system is given below.The system is a/an |
| A. | integrator |
| B. | PID controller |
| C. | PD controller |
| D. | proportional controller |
| Answer» C. PD controller | |
| 82. |
A plant has the following transfer function: G (s) = 1(s2+ 0 2s + 1) For a step input it is required that the response settles to within 2% of its final value. The plant setting time is |
| A. | 20 sec |
| B. | 40 sec |
| C. | 35 sec |
| D. | 45 sec |
| Answer» C. 35 sec | |
| 83. |
In the following pick out the time-invariant systems. (i)dy(t) + 5y(t) = u(t)dt (ii) td2y(t) + dy(t) + 2y(t) = v(t)dt2dt (iii)d2y(t) + 5dy(t) + 6y(t) = (t)dt2dt |
| A. | (i) and (iii) |
| B. | (i) and (ii) |
| C. | (ii) and (iii) |
| D. | (i) only |
| Answer» B. (i) and (ii) | |
| 84. |
The Laplace transform of f(t) is F(s). Given F(s) = s2 + 2 The final value f(t) is |
| A. | infinity |
| B. | zero |
| C. | one |
| D. | None of these |
| Answer» B. zero | |
| 85. |
Consider the following overall T.F. for a unity feedback system = 4s2 + 4s + 4Which of the following statements regarding this system are correct? 1. Position error constant KP for the system is 4. 2. The system type one. 3. The velocity error constant Kv for the system is finite. Select the correct answer code |
| A. | 1, 2, 3 |
| B. | 1, 2 |
| C. | 2, 3 |
| D. | s1, 3 |
| Answer» E. | |
| 86. |
The number of roots of the equation 2s4 + s3 + 3s2 + 5s + 7 = 0 that lie in the right half of s plane is |
| A. | zero |
| B. | one |
| C. | two |
| D. | three |
| Answer» D. three | |
| 87. |
The condition of a stability for a unity feedback control system whose open loop transfer function is given by G(s) =e sTs(s + 2) |
| A. | T < 2 |
| B. | T = 2 |
| C. | T > 2 |
| D. | 0 |
| Answer» B. T = 2 | |
| 88. |
The transfer function of the system Ks2 (1 + sT) operated in closed loop mode with unity feedback. The system is |
| A. | Stable |
| B. | Unstable |
| C. | Conditionally stable |
| D. | Marginally stable |
| Answer» C. Conditionally stable | |
| 89. |
The unit step response of a second order linear system with zero initial states is given by C (t) = 1 + 1.25 exp ( 6t) sin (8t tan 1 1.333); t 0 The damping ratio and the undamped natural frequency of oscillation for the system are respectively |
| A. | 0.6 and 10 rad/s |
| B. | 0.6 and 12.5 rad/s |
| C. | 0.8 and 10 rad/s |
| D. | 0.8 and 12.5 rad/s |
| Answer» B. 0.6 and 12.5 rad/s | |
| 90. |
The Laplace transformation of f (t) is F(s) = = s2 + 2the final value of f(t) is |
| A. | infinity |
| B. | zero |
| C. | one |
| D. | None of these |
| Answer» E. | |
| 91. |
The transfer function of the system Ks2 (1 + sT) is operated in open loop mode. The system is |
| A. | Stable |
| B. | Unstable |
| C. | Conditionally stable |
| D. | Marginally stable |
| Answer» C. Conditionally stable | |
| 92. |
The transmittance from A to B in the signal flow graph shown in the figure is |
| A. | |
| B. | |
| C. | |
| D. | |
| Answer» B. | |
| 93. |
Consider the following properties attributed to state model of a system 1. State model is unique 2. State model can be derived from the system transfer function 3. State model can be derived from time variant systems. Of these statements |
| A. | 1, 2 and 3 are correct |
| B. | 1 and 2 are correct |
| C. | 2 and 3 are correct |
| D. | 1 and 3 are correct |
| Answer» D. 1 and 3 are correct | |
| 94. |
A system has transfer function 1 s 1 + s it is a |
| A. | non-minimum phase system |
| B. | minimum phase system |
| C. | low phase system |
| D. | second order system |
| Answer» B. minimum phase system | |
| 95. |
A linear second-order system with the transfer functionG(s) =49s2 + 8s + 49 is initially at rest and is subject to a step input signal. The response of the system will exhibit a peak overshoot of |
| A. | 16% |
| B. | 9% |
| C. | 2% |
| D. | zero |
| Answer» D. zero | |
| 96. |
The Transfer function of a system is KT + s What is the steady state error when applied u(t) to closed loop system with unity feedback |
| A. | K + T |
| Answer» D. | |
| 97. |
Consider the following statements regarding time-domain analysis of a control system 1. Derivative control improves system s transient performance 2. Integral control does not improve system s steady state performance 3. Integral control can convert a second order system into a third order system. Of these statements |
| A. | 1 and 2 are correct |
| B. | 1 and 3 are correct |
| C. | 2 and 3 are correct |
| D. | 1, 2 and 3 are correct |
| Answer» C. 2 and 3 are correct | |
| 98. |
It is given that G (s) = 1s2 (s + 2) . This system in a closed loop with unity feedback. What is the order and type of the closed loop system? |
| A. | 2 and 3 |
| B. | 3 and 2 |
| C. | 3 and 3 |
| D. | 2 and 2 |
| Answer» C. 3 and 3 | |
| 99. |
Given: KK |
| A. | 0.01 |
| B. | 0.1 |
| C. | 1.0 |
| D. | 10 |
| Answer» C. 1.0 | |
| 100. |
The state representation of a second order system is |
| A. | 1, 2 and 3 are correct |
| B. | 1 and 2 are correct |
| C. | 2 and 3 are correct |
| D. | 1 and 3 are correct |
| Answer» D. 1 and 3 are correct | |