page 3 | Control Systems MCQ Questions & Answers

Q31. The step response of a system is \((1+e^{-3t})\). It is cascaded with another control block with impulse response of \(e^{-2t}\). The transfer function of the cascaded combination is

\(\frac{1}{s(s+3)}\)

\(\frac{2s+3}{(s+2)(s+3)}\)

\(\frac{2}{(s+1)(s+2)}\)

\(\frac{1}{s(s+2)}\)

Q32. If the complex poles of a system have greater real parts, then the overshoot is

Less

More

Not affected

Sometimes less and sometimes more

Q33. The frequency at which the phase versus frequency plot of the control system crosses \(-180^o\) line is known as:

resonant frequency

natural frequency

phase crossover frequency

gain crossover frequency

Q34. The characteristic equation of the system is \(s^4+s^3-3s^2-s+2=0\), the system will be_____.

stable

unstable

not defined

limitedly stable

Q35. Which of the following is a closed loop system?

auto-pilot for an aircraft

Car starter

Electric switch

DC generator

Q36. What is the overall transfer function \(\frac{C(s)}{R(s)}\) for the block diagram shown in figure:

\(G_1G_2+G_2G_3\)

\(\frac{G_1+G_2}{1+G_3H_1}\)

\(\frac{G_1G_2+G_2G_3}{1+G_2H_2}\)

\(\frac{G_1G_2+G_2G_3}{1+G_1G_2G_3H_1}\)

Q37. A closed loop system is distinguished from open loop system by which of the following

Servomechanism

Feedback

Output pattern

Input pattern

Q38. Zero initial condition for a system means

input reference signal is zero

zero stored energy

no initial movement of moving parts

system is at rest and no energy is stored in any of its components

Q39. Which of the following statements is correct for any closed loop system ?

All the co-efficients can have zero value

All the co-efficients are always non-zero

Only one of the static error co-efficients has a finite non-zero value

None of the above

Q40. Which of the following is the input to a controller ?

Servo signal

Desired variable value

Error signal

Sensed signal

MCQ

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