Control Systems — Part 2 MCQs with Explanations

Both A and B is the correct answer to “A conditionally stable system is stable for the value of gain between two critical values. It is unstable if”. This question is standard in competitive examination syllabi for Control Systems.

Surface wound with stationary rotor is the correct answer to “Which dc servomotor requires strongest permanent magnet”. This question is standard in competitive examination syllabi for Control Systems.

Load cell is the correct answer to “Which of the following is used to obtain output position in a position control system”. This question is standard in competitive examination syllabi for Control Systems.

Voltage is the correct answer to “Temperature is analogous to”. This question is standard in competitive examination syllabi for Control Systems.

Routh criterion can be used by substituting a small positive number for zero and completing the array is the correct answer to “If any term in the first column of a Routh array becomes zero, then”. This question is standard in competitive examination syllabi for Control Systems.

Heat flow is the correct answer to “The charge q in the electrical system is analogous to which thermal system quantity”. This question is standard in competitive examination syllabi for Control Systems.

0.60 is the correct answer to “For open loop transfer function of a unit feedback is $$G\left( s \right) = \frac{1}{{s\left( {s + 2} \right)}},$$ having peak overshoot 10%. Find damping ratio.”. This question is standard in competitive examination syllabi for Control Systems.

a-4, b-1, c-2, d-3 is the correct answer to “Match List-I with List-II and select the correct answer, using the options given below: List-I List-II a. Synchro 1. Amplifier b. Amplidyne 2. Actuator c. Servo motor 3. Compensator d. RC network 4. Transducer”. This question is standard in competitive examination syllabi for Control Systems.

$$\frac{{39}}{{16}}$$ is the correct answer to “The characteristic equation of a control system is given as s 4 + 4s 3 + 4s 2 + 3s + K = 0 What is the value of K for which this system is marginally stable”. This question is standard in competitive examination syllabi for Control Systems.

1 and 3 is the correct answer to “Consider the following statements about a proportional plus derivative controller 1. The maximum or peak overshoot is less 2. The stability of the system is less 3. The stability of the system is increased 4. The settling time is increases Which of the above statements are correct”. This question is standard in competitive examination syllabi for Control Systems.

Better rigidity is the correct answer to “In hydraulic controllers, the advantage of flapper valve over piston valve is the:”. This question is standard in competitive examination syllabi for Control Systems.

2-φ induction motor is the correct answer to “The ac motor used in servo applications is a”. This question is standard in competitive examination syllabi for Control Systems.

Underdamped system is the correct answer to “Overall transfer function of a system is given as $$G\left( s \right) = \frac{{2s + 1}}{{{s^2} + 2s + 5}}.$$ The system is characterized as”. This question is standard in competitive examination syllabi for Control Systems.

$${e_{ss}} = \frac{F}{K}$$ is the correct answer to “Consider a unity feedback control system whose open loop transfer function is $$G\left( s \right) = \frac{K}{{s\left( {Js + F} \right)}}$$ Then for unit ramp input steady state error is given as”. This question is standard in competitive examination syllabi for Control Systems.

underdamped is the correct answer to “If the characteristic equation of a closed-loop system is s 2 + 2s + 2 = 0, then the system is”. This question is standard in competitive examination syllabi for Control Systems.

1.41 and 45° is the correct answer to “What are the gain and phase angle of a system having the transfer function G(s) = (s + 1) at a frequency of 1 rad/sec”. This question is standard in competitive examination syllabi for Control Systems.

Both controllable and observable is the correct answer to “Consider a system described by the state model \[\mathop X\limits^. = \left[ {\begin{array}{*{20}{c}} 2&1\\ { - 1}&2 \end{array}} \right]X + \left[ \begin{array}{l} 1\\ 1 \end{array} \right]U{\rm{ and }}Y = \left[ {1\,\,1} \right]X\] The system is:”. This question is standard in competitive examination syllabi for Control Systems.

1, 2 and 4 is the correct answer to “The signal flow diagram for a certain feedback control system is shown in figure Now consider the following set of equations for the nodes 1. x 2 = a 1 x 1 + a 9 x 3 2. x 3 = a 2 x 2 + a 8 x 4 3. x 4 = a 3 x 3 + a 5 x 2 4. x 5 = a 4 x 4 + a 6 x 2 Which of the following are correct”. This question is standard in competitive examination syllabi for Control Systems.

666.25 is the correct answer to “Consider an open - loop transfer function $$G\left( s \right) = \frac{1}{{\left( {s + 2} \right)\left( {s + 4} \right)\left( {{s^2} + 6s + 25} \right)}}.$$ What is the value of k which causes sustained oscillation in the closed - loop system”. This question is standard in competitive examination syllabi for Control Systems.

Phase lead compensator is the correct answer to “A composite R-C network yielded the following transfer function when calculated from its components: $$T\left( s \right) = \frac{{C\left( s \right)}}{{R\left( s \right)}} = \frac{{1 + 21s + 20{s^2}}}{{1 + 11s + 10{s^2}}}$$ This network can be used as which one of the following”. This question is standard in competitive examination syllabi for Control Systems.

1 is the correct answer to “In a synchro error detection, the output voltage is proportional to [ω(t)] n , where ω(t) is the rotor velocity and n equals to”. This question is standard in competitive examination syllabi for Control Systems.

Coincide with the poles is the correct answer to “If the gain of the system is reduced to zero value, the roots of the system in the s-plane:”. This question is standard in competitive examination syllabi for Control Systems.

\[\frac{{2s + 1}}{{{s^2} + 2s + 3}}\] is the correct answer to “For a state space representation of a system \[{\rm{A}} = \left[ {\begin{array}{*{20}{c}} 0&1\\ { - 3}&{ - 2} \end{array}} \right],\,{\rm{B}} = \left[ \begin{array}{l} 0\\ 1 \end{array} \right]\] and C = [1 2] . Then transfer function of system would be:”. This question is standard in competitive examination syllabi for Control Systems.

Only 1 is the correct answer to “Consider the following statements regarding the asymptotic Bode plots used for frequency response analysis: 1. The deviation of the actual magnitude response for a zero on real axis is 3 dB at the corner frequency. 2. The phase angle for a pair of complex conjugate poles at undamped frequency depends upon the value of damping ratio. Which of the statements given above is/are correct”. This question is standard in competitive examination syllabi for Control Systems.

Product of length of vectors from poles/Product of length of vectors from zeros is the correct answer to “In root locus method, the value of K is obtained as”. This question is standard in competitive examination syllabi for Control Systems.

0.01 is the correct answer to “Consider a unity feedback system having a transfer function $$G\left( s \right) = \frac{{100}}{{s\left( {0.1s + 1} \right)}}$$ is subjected to ramp input. The steady-state error is:”. This question is standard in competitive examination syllabi for Control Systems.

$$Ks$$ is the correct answer to “The transfer function of a tachometer is of the form”. This question is standard in competitive examination syllabi for Control Systems.

K > 50 is the correct answer to “A unity feedback system has $$G\left( s \right) = \frac{{K\left( {2s + 1} \right)}}{{s\left( {4s + 1} \right){{\left( {s + 1} \right)}^2}}}$$ What is the value of K if the steady-state value of error is to be less than 0.1 when an input r(t) = 1 + 5t is applied”. This question is standard in competitive examination syllabi for Control Systems.

Steady state error, accuracy is the correct answer to “If the output of the system at steady state doesn't agree with the input, then the system is said to have . . . . . . . . which determines the . . . . . . . . of the system.”. This question is standard in competitive examination syllabi for Control Systems.

0.01 is the correct answer to “The asymptotic bode plot for the gain magnitude of a minimum phase system G(s) is shown in figure below. The steady state error for the ramp input is”. This question is standard in competitive examination syllabi for Control Systems.

Unstable is the correct answer to “Check the system with characteristic equation F(s) = s 4 + 3s 3 + 2s 2 + s + 1 for stability.”. This question is standard in competitive examination syllabi for Control Systems.

Nyquist Plot is the correct answer to “. . . . . . . . indicate not only whether a system is stable, but also its degree of stability and how stability may be improved if necessary.”. This question is standard in competitive examination syllabi for Control Systems.

By use of high proportional band is the correct answer to “A process is controlled by PID controller. The sensor has high measurement noise. How can this effect be reduced”. This question is standard in competitive examination syllabi for Control Systems.

oscillatory is the correct answer to “A system with a unity gain margin and zero phase margin is . . . . . . . .”. This question is standard in competitive examination syllabi for Control Systems.

Exponentially increasing is the correct answer to “What is the time response of a system whose poles lie on the right hand side of s-plane”. This question is standard in competitive examination syllabi for Control Systems.

$$x\left( t \right) = \sin t$$ is the correct answer to “Consider the mechanical system shown in the given figure. If the system is set into motion by unit impulse force, the equation of the resulting oscillation will be:”. This question is standard in competitive examination syllabi for Control Systems.

Increase the effective damping in the system is the correct answer to “In position control systems, Tachogenerator feedback is used to:”. This question is standard in competitive examination syllabi for Control Systems.

Both are reduced is the correct answer to “A tachometer feedback is used as an inner loop in a position control servo-system. What is the effect of feedback on the gain of the sub-loop incorporating tachometer and on the effective time constant of the system”. This question is standard in competitive examination syllabi for Control Systems.

AC servomotor is the correct answer to “Which of the following can be used as a tachogenerator in control system”. This question is standard in competitive examination syllabi for Control Systems.

Gain margin and phase margin are the measure of the degree of stability is the correct answer to “Which one of the following statements is correct in respect of the theory of stability”. This question is standard in competitive examination syllabi for Control Systems.