Control Systems MCQ Questions & Answers

51

The system represented by the state variable model \[\mathop X\limits^. = \left[ {\begin{array}{*{20}{c}} 0&{ - 1}\\ 1&{ - 2} \end{array}} \right]X + \left[ \begin{array}{l} 1\\ 2 \end{array} \right]U\] is:

A) Oscillatory B) Critically damped C) Overdamped D) Underdamped

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Answer & Solution

Answer: Option B

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52

Consider unity feedback system with forward path transfer function $$\frac{{25}}{{s\left( {s + 5} \right)}};$$ what are the values of peak time and settling time?

A) 1.6 sec, 0.726 sec B) 0.726 sec, 1.6 sec C) 0.5 sec, 0.726 sec D) 0.726 sec, 1 sec

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Answer & Solution

Answer: Option B

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53

A system with gain margin close to unity or a phase margin close to zero is:

A) relatively stable B) oscillatory C) stable D) highly stable

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Answer & Solution

Answer: Option B

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54

Consider the state space system expressed by the signal flow diagram in the figure.
The corresponding system is
Control Systems mcq question image

A) always controllable B) always observable C) always stable D) always unstable

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Answer & Solution

Answer: Option A

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55

The loop transfer function of an LTI system is $$G\left( s \right)H\left( s \right) = \frac{{K\left( {s + 1} \right)\left( {s + 5} \right)}}{{s\left( {s + 2} \right)\left( {s + 3} \right)}}.$$ For K > 0, the point on the real axis final DOES NOT belong to the root locus of the system is

A) -0.5 B) -2.5 C) -3.5 D) -5.5

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Answer & Solution

Answer: Option C

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56

A plant transfer function is given as $$G\left( s \right) = \left( {{K_P} + \frac{{{K_I}}}{s}} \right)\left( {\frac{1}{{s\left( {s + 2} \right)}}} \right).$$ When the plant operates in a unity feedback configuration, the condition for the stability of the closed loop system is

A) $${K_P} > \frac{{{K_I}}}{2} > 0$$ B) $$2{K_I} > {K_P} > 0$$ C) $$2{K_I} < {K_P}$$ D) $$2{K_I} > {K_P}$$

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Answer & Solution

Answer: Option A

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57

When all the roots of characteristic equation are found in the left half of s-plane, the system response due to initial condition will:

A) Increase to infinity as time approaches infinity B) Decreases to zero as time approaches infinity C) Remain constant for all time D) Be oscillating

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Answer & Solution

Answer: Option B

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58

The polar diagram of conditionally stable system for open loop gain k = 1 is shown in the figure. The open loop transfer function of the system is known to be stable. The closed loop system is stable for
Control Systems mcq question image

A) $$K < 5{\text{ and }}\frac{1}{2} < K < \frac{1}{8}$$ B) $$K < \frac{1}{8}{\text{ and }}\frac{1}{2} < K < 5$$ C) $$K < \frac{1}{8}{\text{ and }}5 < K$$ D) $$K < \frac{1}{8}{\text{ and }}K < 5$$

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Answer & Solution

Answer: Option B

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59

The open loop transfer function of a system is $$G\left( s \right)H\left( s \right) = \frac{K}{{\left( {1 + s} \right)\left( {1 + 2s} \right)\left( {1 + 3s} \right)}}$$
The phase crossover frequency ω_pc is:

A) $$\sqrt 2 $$ B) 1 C) zero D) $$\sqrt 3 $$

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Answer & Solution

Answer: Option B

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60

The most commonly used input signal (s) in control system is/are

A) Step function B) Ramp or velocity function C) Accelerating function D) All of the above

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Answer & Solution

Answer: Option A

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Control Systems MCQ Questions & Answers | ECE