MCQOPTIONS
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MCQOPTIONS
This section includes 108 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 constant M-circle represented by the equation x^2+2.25x+y^2=-1.25 has the value of M equal to: |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 52. |
Assertion (A): Relative stability of the system reduces due to the presence of transportation lag.Reason (R): Transportation lag can be conveniently handled by Bode plot. |
| A. | Both A and R are true but R is correct explanation of A |
| B. | Both A and R are true but R is correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» C. A is true but R is false | |
| 53. |
The forward path transfer function of a unity feedback system is given by G(s) = 100/(s2+10s+100). The frequency response of this system will exhibit the resonance peak at: |
| A. | 10 rad/sec |
| B. | 8.66 rad/sec |
| C. | 7.07 rad/sec |
| D. | 5rad/sec |
| Answer» D. 5rad/sec | |
| 54. |
The gain margin (in dB) of a system having the loop transfer functionG(s) H(s) = 2 / s(s+1) is |
| A. | 0 |
| B. | 3 |
| C. | 6 |
| D. | 8 |
| Answer» E. | |
| 55. |
Which one of the following statements is correct?Nichol's chart is useful for the detailed study of: |
| A. | Closed loop frequency response |
| B. | Open loop frequency response |
| C. | Close loop and open loop frequency responses |
| D. | None of the mentioned |
| Answer» B. Open loop frequency response | |
| 56. |
The unit circle of the Nyquist plot transforms into 0dB line of the amplitude plot of the Bode diagram at |
| A. | 0 frequency |
| B. | Low frequency |
| C. | High frequency |
| D. | Any frequency |
| Answer» E. | |
| 57. |
Consider the following statements:The gain margin and phase margin of an unstable system may respectively be1. Positive, positive2. Positive, negative3. Negative, positive4. Negative, negativeOf these statements |
| A. | 1 and 4 are correct |
| B. | 1 and 2 are correct |
| C. | 1, 2 and 3 are correct |
| D. | 2,3 and 4 are correct |
| Answer» E. | |
| 58. |
If the system matrix of a linear time invariant continuous system is given byIts characteristic equation is given by: |
| A. | s2+5s+3=0 |
| B. | s2-3s-5=0 |
| C. | s2+3s+5=0 |
| D. | s2+s+2=0 |
| Answer» B. s2-3s-5=0 | |
| 59. |
The corner frequencies are |
| A. | 0 and 1 |
| B. | 0 and 2 |
| C. | 0 and 1 |
| D. | 1 and 2 |
| Answer» E. | |
| 60. |
The open loop transfer function of a system is :G(s) H(s) =K/ (1+s) (1+2s) (1+3s)The phase crossover frequency wpc is: |
| A. | √2 |
| B. | 1 |
| C. | Zero |
| D. | √3 |
| Answer» C. Zero | |
| 61. |
A control system whose step response is -0.5(1+e-2t) is cascaded to another control block whose impulse response is e-t. What is the transfer function of the cascaded combination? |
| A. | 1/(s+2)(s+1) |
| B. | 1/(s+1)s |
| C. | 1/(s+3) |
| D. | 0.5/(s+1)(s+2) |
| Answer» B. 1/(s+1)s | |
| 62. |
Signal flow graphs: |
| A. | They apply to linear systems |
| B. | The equation obtained may or may not be in the form of cause or effect |
| C. | Arrows are not important in the graph |
| D. | They cannot be converted back to block diagram |
| Answer» B. The equation obtained may or may not be in the form of cause or effect | |
| 63. |
Gear train in the motor is used to reduce the gear ratio? |
| A. | True |
| B. | False |
| Answer» C. | |
| 64. |
The advantage of block diagram representation is that it is possible to evaluate the contribution of each component to the overall performance of the system. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 65. |
Tachometer feedback in a D.C. position control system enhances stability? |
| A. | True |
| B. | False |
| Answer» B. False | |
| 66. |
A synchro Transmitter is used with control transformer for: |
| A. | Feedback |
| B. | Amplification |
| C. | Error detection |
| D. | Remote sensing |
| Answer» D. Remote sensing | |
| 67. |
Assertion (A): Servomotors have heavier rotors and lower R/X ratio as compared to ordinary motors of similar ratings.Reason (R): Servomotor should have smaller electrical and mechanical time constants for faster response. |
| A. | Both A and R are true and R is the correct explanation of A |
| B. | Both A and R are true but R is not correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» E. | |
| 68. |
Which of the following is an example of an open loop system? |
| A. | Household Refrigerator |
| B. | Respiratory system of an animal |
| C. | Stabilization of air pressure entering into the mask |
| D. | Execution of program by computer |
| Answer» E. | |
| 69. |
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: |
| A. | (s+2)/(s+1) |
| B. | (s+1)/(s+2) |
| C. | 2(s+1)/(s+2) |
| D. | (s+1)/2(s+2) |
| Answer» D. (s+1)/2(s+2) | |
| 70. |
The output of an first order hold between two consecutive sampling instants is: |
| A. | Constant |
| B. | Quadratic Function |
| C. | Ramp Function |
| D. | Exponential Function |
| Answer» D. Exponential Function | |
| 71. |
For a tachometer, if a(t) is the rotor displacement, e(t) is the output voltage and K is the tachometer constant, then the transfer function is given by: |
| A. | Ks2 |
| B. | K/s |
| C. | Ks |
| D. | K |
| Answer» D. K | |
| 72. |
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______________ |
| A. | Overall gain of the system |
| B. | Stability |
| C. | Bandwidth |
| D. | Speed |
| Answer» B. Stability | |
| 73. |
Assertion (A): DC servomotors are more commonly used in armature controlled mode than field controlled mode.Reason (R): Armature controlled Dc motors have higher starting torque than fiels controlled motors. |
| A. | Both A and R are true and R is the correct explanation of A |
| B. | Both A and R are true but R is not correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» B. Both A and R are true but R is not correct explanation of A | |
| 74. |
The loop transfer function of a system is given by G(s) H(s) =10e-Ls/s. The phase crossover frequency is 5rad/s. The value of the dead time L is |
| A. | π/20 |
| B. | π/10 |
| C. | -π/20 |
| D. | Zero |
| Answer» C. -π/20 | |
| 75. |
Nichol's chart: |
| A. | Constant gain and constant phase shift loci of the closed-loop system. |
| B. | Plot of loop gain with the variation in frequency |
| C. | Circles of constant gain for the closed loop transfer function |
| D. | Circles of constant phase shift for the closed loop transfer function |
| Answer» C. Circles of constant gain for the closed loop transfer function | |
| 76. |
The equation 2s4+s3+3s2+5s+10=0 has roots in the left half of s-plane: |
| A. | One |
| B. | Two |
| C. | Three |
| D. | Four |
| Answer» C. Three | |
| 77. |
The open loop transfer function of a system is G(s) H(s)= K / (1+s)(1+2s)(1+3s)The phase cross over frequency ωc is |
| A. | V2 |
| B. | 1 |
| C. | Zero |
| D. | V3 |
| Answer» C. Zero | |
| 78. |
All pass system and minimum phase system constitute_________________ |
| A. | Pole must lie on left plane |
| B. | Minimum phase system |
| C. | Non-minimum phase system |
| D. | Both must lie on right plane |
| Answer» D. Both must lie on right plane | |
| 79. |
If a system has an open loop transfer function1-s / 1+s, then the gain of the system at frequency of 1 rad/s will be |
| A. | 1 |
| B. | 1/2 |
| C. | Zero |
| D. | -1 |
| Answer» E. | |
| 80. |
Consider the following statements:1. The effect of feedback is to reduce the system error2. Feedback increases the gain of the system in one frequency range but decreases in another3. Feedback can cause a system that is originally stable to become unstableWhich of these statements are correct. |
| A. | 1,2 and 3 |
| B. | 1 and 2 |
| C. | 2 and 3 |
| D. | 1 and 3 |
| Answer» D. 1 and 3 | |
| 81. |
The forward path transfer function of a unity feedback system is given by G(s) = 1/(1+s)^2.What is the phase margin of the system? |
| A. | -π rad |
| B. | 0 rad |
| C. | π/2 rad |
| D. | π rad |
| Answer» E. | |
| 82. |
The frequency at which the Nyquist diagram cuts the unit circle is known as: |
| A. | Gain crossover frequency |
| B. | Phase crossover frequency |
| C. | Damping frequency |
| D. | Corner frequency |
| Answer» B. Phase crossover frequency | |
| 83. |
The polar plot of the open loop transfer function of a feedback control system intersects the real axis at -2. The gain margin of the system is |
| A. | -5dB |
| B. | 0dB |
| C. | -6dB |
| D. | 40dB |
| Answer» D. 40dB | |
| 84. |
Consider the function F (s) =5/s (s2+s+2) , where F (s) is the Laplace transform f (t). Then the final value theorem is equal to |
| A. | 5 |
| B. | 5/2 |
| C. | Zero |
| D. | Infinity |
| Answer» C. Zero | |
| 85. |
Backlash in a stable control system may cause: |
| A. | Under damping |
| B. | Over damping |
| C. | High level oscillations |
| D. | Low level oscillations |
| Answer» E. | |
| 86. |
Oscillations in output response is due to : |
| A. | Positive feedback |
| B. | Negative feedback |
| C. | No feedback |
| D. | None of the mentioned |
| Answer» B. Negative feedback | |
| 87. |
In case of DC servomotor, the back emf is equivalent to an 'electric friction' which tends to: |
| A. | Slowly decrease the stability of the system |
| B. | Improve stability of the system |
| C. | Very rapidly decrease the stability of the system |
| D. | Have no effect of stability |
| Answer» C. Very rapidly decrease the stability of the system | |
| 88. |
Transfer function of the system is defined as the ratio of Laplace output to Laplace input considering initial conditions________ |
| A. | 1 |
| B. | 2 |
| C. | 0 |
| D. | infinite |
| Answer» D. infinite | |
| 89. |
Signal flow graphs are reliable to find transfer function than block diagram reduction technique. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 90. |
A gantry robot consists of a manipulator mounted on an overhead system that allows movement only in ________ plane. |
| A. | Horizontal |
| B. | Inclined |
| C. | Vertical |
| D. | None of the mentioned |
| Answer» B. Inclined | |
| 91. |
The overall transfer function from block diagram reduction for cascaded blocks is : |
| A. | Sum of individual gain |
| B. | Product of individual gain |
| C. | Difference of individual gain |
| D. | Division of individual gain |
| Answer» C. Difference of individual gain | |
| 92. |
A tachometer is added to servomechanism because: |
| A. | It is easily adjustable |
| B. | It can adjust damping |
| C. | It reduces steady state error |
| D. | It converts velocity of the shaft to a proportional Dc voltage |
| Answer» C. It reduces steady state error | |
| 93. |
Constant M- loci: |
| A. | Constant gain and constant phase shift loci of the closed-loop system. |
| B. | Plot of loop gain with the variation in frequency |
| C. | Circles of constant gain for the closed loop transfer function |
| D. | Circles of constant phase shift for the closed loop transfer function |
| Answer» E. | |
| 94. |
In a feedback control system, phase margin(PM) is1. Directly proportional to G2. Inversely proportional to G3. Independent of G4. Zero when G =0Which of the above statements are correct? |
| A. | 1 and 2 |
| B. | 2 and 3 |
| C. | 3 and 4 |
| D. | 1 and 4 |
| Answer» E. | |
| 95. |
The impulse response of a LTI system is a unit step function, then the corresponding transfer function is |
| A. | 1/s |
| B. | 1/s2 |
| C. | 1 |
| D. | s |
| Answer» B. 1/s2 | |
| 96. |
A system with gain margin close to unity and phase margin close to zero is : |
| A. | Highly stable |
| B. | Oscillatory |
| C. | Relatively stable |
| D. | Unstable |
| Answer» D. Unstable | |
| 97. |
Nichol's chart is useful for the detailed study and analysis of: |
| A. | Closed loop frequency response |
| B. | Open loop frequency response |
| C. | Close loop and open loop frequency responses |
| D. | open loop and Close loop frequency responses |
| Answer» B. Open loop frequency response | |
| 98. |
Frequency range of bode magnitude and phases are decided by : |
| A. | The lowest and higher important frequencies of dominant factors of the OLTF |
| B. | The lowest and highest important frequencies of all the factors of the open loop transfer function |
| C. | Resonant frequencies of the second factors |
| D. | None of the above |
| Answer» E. | |
| 99. |
The gain margin in dBs of a unity feedback control system whose open loop transfer function, G(s) H(s) =1/s(s+1) is |
| A. | 0 |
| B. | 1 |
| C. | -1 |
| D. | ∞ |
| Answer» E. | |
| 100. |
The LVDT is used in the measurement of: |
| A. | Displacement |
| B. | Acceleration |
| C. | Velocity |
| D. | Humidity |
| Answer» B. Acceleration | |