Control Systems Multiple Choice Questions & Answers

 1. The viscous friction co-efficient, in force-voltage analogy, is analogous to
a) charge
b) resistance
c) reciprocal of inductance
d) reciprocal of conductance
Answer: resistance
2. In a control system the output of the controller is given to
a) final control element
b) amplifier
c) comparator
d) sensor
Answer: final control element
3. The capacitance, in force-current analogy, is analogous to
a) momentum
b) velocity
c) displacement
d) mass
Answer: mass
4. The transient response of a system is mainly due to
a) inertia forces
b) internal forces
c) stored energy
d) friction
Answer: stored energy
5. 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: The time constant and suppress the oscillations
6. The on-off controller is a _____ system.
a) digital
b) linear
c) non-linear
d) discontinuous
Answer: discontinuous
7. 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: The system is highly oscillatory
8. 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: Noise is proportional to band width
9. 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: Oscillator
10. 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: Signal flow graph
11.  A controller, essentially, is a
a) sensor
b) clipper
c) comparator
d) amplifier
Answer: comparator
12. Which of the following is the not the ideal input to a controller ?
a) Servo signal
b) Desired variable value
c) Error signal
d) Sensed signal
Answer: Servo signal
13. The transient response, with feedback system, _________. 
a) rises slowly
b) rises quickly
c) decays slowly
d) decays quickly
Answer: decays quickly
14. The temperature, under thermal and electrical system analogy, is considered analogous to
a) voltage
b) current
c) capacitance
d) charge
Answer: voltage
15. In electrical-pneumatic system analogy the current is considered analogous to
a) velocity
b) pressure
c) air flow
d) air flow rate
Answer: air flow rate
16. In a system low friction co-efficient facilitates
a) reduced velocity lag error
b) increased velocity lag error
c) increased speed of response
d) reduced time constant of the system
Answer: reduced velocity lag error
17. With feedback __________ increases.
a) system stability
b) sensitivity
c) gain
d) effects of disturbing signals
Answer: system stability
18. In force-voltage analogy, velocity is analogous to
a) current
b) charge
c) inductance
d) capacitance
Answer: current
19. In thermal-electrical analogy charge is considered analogous to
a) heat flow
b) reciprocal of heat flow
c) reciprocal of temperature
d) temperature
Answer: temperature
20. Mass, in force-voltage analogy, is analogous to
a) charge
b) current
c) inductance
d) resistance
Answer: inductance
21. 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: Unit impulse input signal
22. In a stable control system backlash can cause which of the following ?
a) Underdamping
b) Overdamping
c) Poor stability at reduced values of open loop gain
d) Low-level oscillations
Answer: Low-level oscillations
23. ______ Signal will become zero when the feedback signal and reference signs are equal.
a) Input
b) Actuating
c) Feedback
d) Reference
Answer: Actuating
24. 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) Non-linear systems
Answer: Linear and time-in variant systems
25. 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: disturbance
26. __________ is the reference input minus the primary feedback.
a) Manipulated variable
b) Zero sequence
c) Actuating signal
d) Primary feedback
Answer: Actuating signal
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 signal
Answer: The system is at rest and no energy is stored in any of its components
28. 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: All of the above
29. 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: head
30. Which of the following statements is correct for any closed loop system ?
a) All the co-efficients can have zero value
b) All the co-efficients are always non-zero
c) Only one of the static error co-efficients has a finite non-zero value
d) None of the above
Answer: Only one of the static error co-efficients has a finite non-zero value