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Q 1. A control system working under unknown random actions is called

DRex Electronics

(A) Computer control system
(B) Digital data system
(C) Stochastic control system
(D) Adaptive control system

Answer: Option C

Q 2. By which of the following the control action is determined when a man walks along a path?

(A) Brain
(B) Hands
(C) Legs
(D) Eyes

Answer: Option D

Q 3. As a result of introduction of negative feedback which of the following will not decrease?

(A) Band width
(B) Overall gain
(C) Distortion
(D) Instability

Answer: Option A

Q 4. In a control system the output of the controller is given to

(A) Final control element
(B) Amplifier
(C) Comparator
(D) Sensor

Answer: Option A

Q 5. A signal other than the reference input that tends to affect the value of controlled variable is known as

(A) Disturbance
(B) Command
(C) Control element
(D) Reference input

Answer: Option A

Q 6. In a system low friction coefficient facilitates

(A) Reduced velocity lag error
(B) Increased velocity lag error
(C) Increased speed of response
(D) Reduced time constant of the system

Answer: Option A

Q 7. The type-2 system has ________ at the origin.

(A) No net pole
(B) Net pole
(C) Simple pole
(D) Two poles

Answer: Option D

Q 8. Addition of zeros in transfer function causes which of the following?

(A) Lead-compensation
(B) Lag-compensation
(C) Lead-lag compensation
(D) None of the above

Answer: Option B

Q 9. In pneumatic control systems the control valve used as final control element converts

(A) Pressure signal to electric signal
(B) Pressure signal to position change
(C) Electric signal to pressure signal
(D) Position change to pressure signal

Answer: Option B

Q 10. When the initial conditions of a system are specified to be zero it implies that the system is

(A) At rest without any energy stored in it
(B) Working normally with reference input
(C) Working normally with zero reference input
(D) At rest but stores energy

Answer: Option D

Q 11. An amplidyne can give which of the following characteristics?

(A) Constant current
(B) Constant voltage
(C) Constant current as well as constant voltage
(D) Constant current, constant voltage and constant power

Answer: Option D

Q 12. A.C. servomotor is basically a

(A) Universal motor
(B) Single phase induction motor
(C) Two phase induction motor
(D) Three phase induction motor

Answer: Option C

Q 13. In an open loop control system

(A) Output is independent of control input
(B) Output is dependent on control input
(C) Only system parameters have effect on the control output
(D) None of the above

Answer: Option A

Q 14. A car is running at a constant speed of 50 km/h, which of the following is the feedback element for the driver?

(A) Clutch
(B) Eyes
(C) Needle of the speedometer
(D) Steering wheel

Answer: Option C

Q 15. A.C. servomotor resembles

(A) Two phase induction motor
(B) Three phase induction motor
(C) Direct current series motor
(D) Universal motor

Answer: Option A

Q 16. Which of the following statements is correct for a system with gain margin close to unity or a phase margin close to zero?

(A) The system is relatively stable
(B) The system is highly stable
(C) The system is highly oscillatory
(D) None of the above

Answer: Option C

Q 17. In force-voltage analogy, velocity is analogous to

(A) Current
(B) Charge
(C) Inductance
(D) Capacitance

Answer: Option A

Q 18. By which of the following the system response can be tested better?

(A) Ramp input signal
(B) Sinusoidal input signal
(C) Unit impulse input signal
(D) Exponentially decaying signal

Answer: Option C

Q 19. The position and velocity errors of a type-2 system are

(A) Constant, constant
(B) Constant, infinity
(C) Zero, constant
(D) Zero, zero

Answer: Option C

Q 20. The phase lag produced by transportation relays

(A) Is independent of frequency
(B) Is inversely proportional to frequency
(C) Increases linearly with frequency
(D) Decreases linearly with frequency

Answer: Option C

Q 21. Which of the following is the definition of proportional band of a controller?

(A)  The range of air output as measured variable varies from maximum to minimum
(B) The range of measured variables from set value
(C)  The range of measured variables through which the air output changes from maximum to minimum
(D) Any of the above

Answer: Option C

Q 22. Which of the following is the nonlinearity caused by servomotor?

(A) Static friction
(B) Backlash
(C) Saturation
(D) None of the above

Answer: Option C

Q 23. _________ directly converts temperature into voltage.

(A) Thermocouple
(B) Potentiometer
(C) Gear train
(D) LVDT

Answer: Option A

Q 24. Which of the following is exhibited by Root locus diagrams?

(A) The poles of the transfer function for a set of parameter values
(B) The bandwidth of the system
(C) The response of a system to a step input
(D) The frequency response of a system

Answer: Option A

Q 25. Regenerative feedback implies feedback with

(A) Oscillations
(B) Step input
(C) Negative sign
(D) Positive sign

Answer: Option D

Q 26. For open control system which of the following statements is incorrect?

(A) Less expensive
(B) Recalibration is not required for maintaining the required quality of the output
(C) Construction is simple and maintenance easy
(D) Errors are caused by disturbances

Answer: Option B

Q 27. In a system zero initial condition means that

(A)  The system is at rest and no energy is stored in any of its components
(B) The system is working with zero stored energy
(C) The system is working with zero reference signals
(D) None of the above

Answer: Option A

Q 28. Which of the following is the best method for determining the stability and transient response?

(A) Root locus
(B) Bode plot
(C) Nyquist plot
(D) None of the above

Answer: Option A

Q 29. Technique gives quick transient and stability response

(A) Root locus
(B) Bode
(C) Nyquist
(D) Nichols

Answer: Option A

Q 30. The first order control system, which is well designed, has a

(A) Small bandwidth
(B) Negative time constant
(C) Large negative transfer function pole
(D) None of the above

Answer: Option C

Q 31. If the gain of the critical damped system is increased it will behave as

(A) Oscillatory
(B) Critically damped
(C) Over-damped
(D) Under-damped

Answer: Option D

Q 32. The capacitance, in force-current analogy, is analogous to

(A) Momentum
(B) Velocity
(C) Displacement
(D) Mass

Answer: Option D

Q 33. The transient response, with feedback system,

(A) Rises slowly
(B) Rises quickly
(C) Decays slowly
(D) Decays quickly

Answer: Option D

Q 34. _________ is an open loop control system.

(A) Ward Leonard control
(B) Field controlled D.C. motor
(C) Stroboscope
(D) Metadyne

Answer: Option B

Q 35. Is a part of the human temperature control system?

(A) Digestive system
(B) Perspiration system
(C) Ear
(D) Leg movement

Answer: Option B

Q 36. The initial response when the output is not equal to input is called

(A) Transient response
(B) Error response
(C) Dynamic response
(D) Either of the above

Answer: Option A

Q 37. A control system in which the control action is somehow dependent on the output is known as

(A) Closed loop system
(B) Semi-closed loop system
(C) Open system
(D) None of the above

Answer: Option A

Q 38. Which of the following statements is correct for any closed loop system?

(A) All the coefficients can have zero value
(B) All the coefficients are always nonzero
(C) Only one of the static error coefficients has a finite nonzero value
(D) None of the above

Answer: Option C

Q 39. Mass, in force-voltage analogy, is analogous to

(A) Charge
(B) Current
(C) Inductance
(D) Resistance

Answer: Option C

Q 40. An increase in gain, in most systems, leads to

(A) Smaller damping ratio
(B) Larger damping ratio
(C) Constant damping ratio
(D) None of the above

Answer: Option A

Q 41. Phase margin of a system is used to specify which of the following?

(A) Frequency response
(B) Absolute stability
(C) Relative stability
(D) Time response

Answer: Option C

Q 42. The type 0 system has ________ at the origin.

(A) No pole
(B) Net pole
(C) Simple pole
(D) Two poles

Answer: Option A

Q 43. ________ is not a final control element.

(A) Control valve
(B) Potentiometer
(C) Electro-pneumatic converter
(D) Servomotor

Answer: Option B

Q 44. Which of the following is an electromagnetically device?

(A) Induction relay
(B) Thermocouple
(C) LVDT
(D) Any of the above

Answer: Option C

Q 45. The transfer function technique is considered as inadequate under which of the following conditions?

(A) Systems having complexities and nonlinearities
(B) Systems having stability problems
(C) Systems having multiple input disturbances
(D) All of the above

Answer: Option D

Q 46. In closed loop control system, with positive value of feedback gain the overall gain of the system will

(A) Decrease (B) Increase
(C) Be unaffected
(D) Any of the above

Answer: Option A

Q 47. An automatic toaster is a ________ loop control system.

(A) Open
(B) Closed
(C) Partially closed
(D) Any of the above

Answer: Option A

Q 48. Which of the following should be done to make an unstable system stable?

(A) The gain of the system should be decreased
(B) The gain of the system should be increased
(C) The number of poles to the loop transfer function should be increased
(D) The number of zeros to the loop transfer function should be increased

Answer: Option B

Q 49. The output of a feedback control system must be a function of

(A) Reference and output
(B) Reference and input
(C) Input and feedback signal
(D) Output and feedback signal

Answer: Option A

Q 50. Due to which of the following reasons excessive bond width in control systems should be avoided?

(A) It leads to slow speed of response
(B) It leads to low relative stability
(C) Noise is proportional to band width
(D) None of the above

Answer: Option C

Q 51. In electrical-pneumatic system analogy the current is considered analogous to

(A) Velocity
(B) Pressure
(C) Air flow
(D) Air flow rate

Answer: Option D

Q 52. Signal will become zero when the feedback signal and reference signs are equal.

(A) Input
(B) Actuating
(C) Feedback
(D) Reference

Answer: Option B

Q 53. With feedback _____ increases.

(A) System stability
(B) Sensitivity
(C) Gain
(D) Effects of disturbing signals

Answer: Option A

Q 54. Velocity error constant of a system is measured when the input to the system is unit ________ function.

(A) Parabolic
(B) Ramp
(C) Impulse
(D) Step

Answer: Option B

Q 55. Which of the following can be measured by the use of a tachogenerator?

(A) Acceleration
(B) Speed
(C) Speed and acceleration
(D) Displacement

Answer: Option B

Q 56. A differentiator is usually not a part of a control system because it

(A) Reduces damping
(B) Reduces the gain margin
(C) Increases input noise
(D) Increases error

Answer: Option C

Q 57. Which of the following is an open loop control system?

(A) Field controlled D.C. motor
(B) Ward Leonard control
(C) Metadyne
(D) Stroboscope

Answer: Option A

Q 58. ________ Increases the steady state accuracy.

(A) Integrator
(B) Differentiator
(C) Phase lead compensator
(D) Phase lag compensator

Answer: Option A

Q 59. In a stable control system backlash can cause which of the following?

(A) Under-damping
(B) Over-damping
(C) Poor stability at reduced values of open loop gain
(D) Low-level oscillations

Answer: Option D

Q 60. The transient response of a system is mainly due to

(A) Inertia forces
(B) Internal forces
(C) Stored energy
(D) Friction

Answer: Option C

Q 61. The frequency and time domain are related through which of the following?

(A) Laplace Transform and Fourier Integral
(B) Laplace Transform
(C) Fourier Integral
(D) Either (B) or (C)

Answer: Option A

Q 62. In case of type-1 system steady state acceleration is

(A) Unity
(B) Infinity
(C) Zero
(D) 10

Answer: Option B

Q 63. Which of the following statements is not necessarily correct for open control system?

(A) Input command is the sole factor responsible for providing the control action
(B) Presence of nonlinearities causes malfunctioning
(C) Less expensive
(D) Generally free from problems of nonlinearities

Answer: Option B

Q 64. Zero initial condition for a system means

(A) Input reference signal is zero
(B) Zero stored energy
(C) Net initial movement of moving parts
(D)  System is at rest and no energy is stored in any of its components

Answer: Option D

Q 65. A controller, essentially, is a

(A) Sensor
(B) Clipper
(C) Comparator
(D) Amplifier

Answer: Option C

Q 66. The transfer function is applicable to which of the following?

(A) Linear and time-in variant systems
(B) Linear and time-variant systems
(C) Linear systems
(D) Nonlinear systems

Answer: Option A

Q 67. A conditionally stable system exhibits poor stability at

(A) Low frequencies
(B) Reduced values of open loop gain
(C) Increased values of open loop gain
(D) None of the above

Answer: Option B

Q 68. Which of the following devices is used for conversion of coordinates?

(A) Microsyn
(B) Selsyn
(C) Synchro-resolver
(D) Synchro-transformer

Answer: Option C

 Q 69. With feedback ________ reduces.

(A) System stability
(B) System gain
(C) System stability and gain
(D) None of the above

Answer: Option B

Q 70. In open loop system

(A) The control action depends on the size of the system
(B) The control action depends on system variables
(C) The control action depends on the input signal
(D) The control action is independent of the output

Answer: Option D

Q 71. A closed loop system is distinguished from open loop system by which of the following?

(A) Servomechanism
(B) Feedback
(C) Output pattern
(D) Input pattern

Answer: Option B

Q 72. The band width, in a feedback amplifier.

(A) Remains unaffected
(B) Decreases by the same amount as the gain increase
(C) Increases by the same amount as the gain decrease
(D) Decreases by the same amount as the gain decrease

Answer: Option C

Q 73. In liquid level and electrical system analogy, voltage is considered analogous to

(A) Head
(B) Liquid flow
(C) Liquid flow rate
(D) None of the above

Answer: Option A

Q 74. ________ is the reference input minus the primary feedback.

(A) Manipulated variable
(B) Zero sequence
(C) Actuating signal
(D) Primary feedback

Answer: Option C

Q 75. If a step function is applied to the input of a system and the output remains below a certain level for all the time, the system is

(A) Not necessarily stable
(B) Stable
(C) Unstable
(D) Always unstable

Answer: Option A

Q 76. The effect of error damping is to

(A) Provide larger settling lime
(B) Delay the response
(C) Reduce steady state error
(D) Any of the above

Answer: Option C

Q 77. Which of the following can be measured by LVDT?

(A) Displacement
(B) Velocity
(C) Acceleration
(D) Any of the above

Answer: Option D

Q 78. Any externally introduced signal affecting the controlled output is called a

(A) Feedback
(B) Stimulus
(C) Signal
(D) Gain control

Answer: Option B

Q 79. Transfer function of a system is used to calculate which of the following?

(A) The order of the system
(B) The time constant
(C) The output for any given input
(D) The steady state gain

Answer: Option C

Q 80. Has tendency to oscillate.

(A) Open loop system
(B) Closed loop system
(C) Both (A) and (B)
(D) Neither (A) nor (B)

Answer: Option B

Q 81. A phase lag lead network introduces in the output

(A) Lag at all frequencies
(B) Lag at high frequencies and lead at low frequencies
(C) Lag at low frequencies and lead at high frequencies
(D) None of the above

Answer: Option C

Q 82. The type-1 system has ________ at the origin.

(A) No pole
(B) Net pole
(C) Simple pole
(D) Two poles

Answer: Option C

Q 83. Spring constant in force-voltage analogy is analogous to

(A) Capacitance
(B) Reciprocal of capacitance
(C) Current
(D) Resistance

Answer: Option B

Q 84. The temperature, under thermal and electrical system analogy, is considered analogous to

(A) Voltage
(B) Current
(C) Capacitance
(D) Charge

Answer: Option A

Q 85. The second derivative input signals modify which of the following?

(A) The time constant of the system
(B) Damping of the system
(C) The gain of the system
(D) The time constant and suppress the oscillations

Answer: Option D

Q 86. ________ is a closed loop system.

(A) Autopilot for an aircraft
(B) Direct current generator
(C) Car starter
(D) Electric switch

Answer: Option A

Q 87. A good control system has all the following features except

(A) Good stability
(B) Slow response
(C) Good accuracy
(D) Sufficient power handling capacity

Answer: Option B

Q 88. Technique is not applicable to nonlinear system?

(A) Nyquist Criterion
(B) Quasi linearization
(C) Functional analysis
(D) Phase-plane representation

Answer: Option A

Q 89. In a control system integral error compensation _________ steady state error

(A) Increases
(B) Minimizes
(C) Does not have any effect on
(D) Any of the above

Answer: Option B

Q 90. In thermal-electrical analogy charge is considered analogous to

(A) Heat flow
(B) Reciprocal of heat flow
(C) Reciprocal of temperature
(D) Temperature

Answer: Option D

Q 91. Which of the following devices are commonly used as error detectors in instruments?

(A) Vernistats
(B) Microsyns
(C) Resolvers
(D) Any of the above

Answer: Option D

Q 92. A control system with excessive noise, is likely to suffer from

(A) Saturation in amplifying stages
(B) Loss of gain
(C) Vibrations
(D) Oscillations

Answer: Option A

Q 93. On which of the following factors does the sensitivity of a closed loop system to gain changes and load disturbances depend?

(A) Frequency
(B) Loop gain
(C) Forward gain
(D) All of the above

Answer: Option D

Q 94. In an automatic control system which of the following elements is not used?

(A) Error detector
(B) Final control element
(C) Sensor
(D) Oscillator

Answer: Option D

Q 95. The viscous friction coefficient, in force-voltage analogy, is analogous to

(A) Charge
(B) Resistance
(C) Reciprocal of inductance
(D) Reciprocal of conductance

Answer: Option B

Q 96. From which of the following transfer function can be obtained?

(A) Signal flow graph
(B) Analogous table
(C) Output-input ratio
(D) Standard block system

Answer: Option A

Q 97. Static error coefficients are used as a measure of the effectiveness of closed loop systems for specified ________ input signal.

(A) Acceleration
(B) Velocity
(C) Position
(D) All of the above

Answer: Option D

Q 98. In order to increase the damping of a badly under-damped system which of following compensators may be used?

(A) Phase-lead
(B) Phase-lag
(C) Both (A) and (B)
(D) Either (A) and (B)

Answer: Option A

Q 99. ________ can be extended to systems which are time-varying?

(A) Bode-Nyquist stability methods
(B) Transfer functions
(C) Root locus design
(D) State model representatives

Answer: Option D

Q 100. Which of the following is the output of a thermocouple?

(A) Alternating current
(B) Direct current
(C) A.C. voltage
(D) D.C. voltage

Answer: Option D