Time Response Analysis MCQ

1. A second-order system with a zero at -2 has its poles located at -3 + j4 and -3 – j4 in the s-plane. The undamped natural frequency and the damping factor of the system respectively are

  1. 5 rad/s and 0.6
  2. 3 rad/s and 0.6
  3. 5 rad/s and 0.8
  4. 3 rad/s and 0.8
Answer
Answer. a

2. The transient response of the second-order underdamped system starting from rest is given by

c(t) = Ae-6t sin(8t + θ), t ≥ 0.

The natural frequency of the system is

  1. 100
  2. 10
  3. 9
  4. 8
Answer
Answer. b

3. The steady state response c(t) for an input r(t) = sin2t to a system transfer function \frac{1}{s + 4} is

  1. 0.632 cos2t
  2. 0.316 sin(2t – 26.5°)
  3. sin(2t – 45°)
  4. 0.25 sin2t
Answer
Answer. b

4. For a critically damped system, the closed-loop poles are

  1. real, unequal and negative
  2. complex conjugate with negative real part
  3. real, equal and negative
  4. purely imaginary
Answer
Answer. c

5. The open-loop transfer function of a unity feedback system is \frac{K}{s(s+4)}. For a damping factor of 0.5, the value of the gain K must be set to

  1. 16
  2. 4
  3. 2
  4. 1
Answer
Answer. a

6. A system has a transfer function

\frac{C(s)}{R(s)}=\frac{4}{s^2 + 1.6s + 4}

For a unit step response and 2% tolerance band, the settling time will be

  1. 2 seconds
  2. 3 seconds
  3. 4 seconds
  4. 5 seconds
Answer
Answer. d

7. How many poles does the following function have?

R(s)=\frac{s^3 + 2s + 1}{s^2 + 3s + 2}

  1. 3
  2. 2
  3. 1
  4. 0
Answer
Answer. a

8. In a system, the damping coefficient is -2. The system response will be

  1. Undamped
  2. Oscillations with decreasing magnitude
  3. Oscillations with increasing magnitude
  4. Critically damped
Answer
Answer. c

9. Consider the following statements regarding the effect of adding a pole in the open-loop transfer function on the closed-loop step response:

  1. It increases the maximum overshoot.
  2. It increases the rise time.
  3. It reduces bandwidth.

Which of the above statements are correct

  1. i, ii and iii
  2. i and ii only
  3. i and iii only
  4. ii and iii only
Answer
Answer. a

10. The derivative of a parabolic function becomes

  1. a unit-impulse function
  2. a ramp function
  3. a gate function
  4. a triangular function
Answer
Answer. b

11. In the time-domain specification, decay ratio is the ratio of the

  1. amplitude of the first peak and the steady-state value
  2. amplitudes of the first two successive peaks
  3. peak value to the steady-state value
  4. none of the above
Answer
Answer. b

12. Consider the time response of a second-order system with damping coefficient less than 1 to a unit step input:

  1. It is overdamped.
  2. It is a periodic function.
  3. Time duration between any two consecutive values of 1 is the same.

Which of the above statements is/are correct?

  1. i, ii and iii
  2. i only
  3. ii only
  4. iii only
Answer
Answer. d

13. A sensor requires 30 s to indicate 90% of the response to a step input. If the sensor is a first-order system, the time constant is

[given, loge (0.1) = -2.3]
  1. 15 s
  2. 13 s
  3. 21 s
  4. 28 s
Answer
Answer. b

14. Consider the following input and system types:

Input type System type
Unit step Type ‘0’
Unit ramp Type ‘1’
Unit parabolic Type ‘2’

Which of the following statements are correct?

  1. Unit step input is acceptable to all three types of system.
  2. Type ‘0’ system cannot accept unit parabolic input.
  3. Unit ramp input is acceptable to Type ‘2’ system only.
  1. i and ii only
  2. i and iii only
  3. ii and iii only
  4. i, ii and iii
Answer
Answer. a

15. The characteristic equation of a closed-loop system is s2 + 4s+ 16 = 0. The natural frequency of oscillation and damping constant respectively are

  1. 2 rad/s and 0.5
  2. 2\sqrt{3} rad/s and \frac{1}{\sqrt{3}}
  3. 4 rad/s and 0.5
  4. 4 rad/s and 0.707
Answer
Answer. c

16. The unit impulse response of a system is given as c(t) = -4e-t + 6e-2t. The step response of the same system for t ≥ 0 is equal to

  1. 3e-2t – 4e-t + 1
  2. -3e-2t + 4e-t + 1
  3. -3e-2t + 4e-t – 1
  4. 3e-2t + 4e-t + 1
Answer
Answer. c

17. A unity feedback second-order control system characterized by the open-loop transfer function

G(s) =\frac{K}{s(Js+ B)}

J = moment of inertia, B = damping constant and K = system gain.

The transient response specification which is not affected by system gain variation is

  1. Peak overshoot
  2. Rise time
  3. Settling time
  4. Time to peak overshoot
Answer
Answer. c

18. For a unit step input, a system with forward path transfer function G(s) = 20/s2 and feedback path transfer function H(s) = (s+5) has a steady-state output of

  1. 2
  2. 0.5
  3. 1
  4. 0.2
Answer
Answer. d

19. Consider the open-loop transfer function:

G(s)H(s) =\frac{5(s+1)}{s^2(s+5)(s + 12)}

The steady state error due to a ramp input is

  1. 0
  2. 5
  3. 12
Answer
Answer. d

20. The position and velocity error coefficients for the system of transfer function,

G(s)=\frac{50}{(1+0. 1s)(1+2s)} are respectively

  1. zero and zero
  2. zero and infinity
  3. 50 and zero
  4. 50 and infinity
Answer
Answer. c
error: Content is protected !!

Adblocker detected! Please consider reading this notice.

We've detected that you are using AdBlock Plus or some other adblocking software which is preventing the page from fully loading.

We don't have any banner, Flash, animation, obnoxious sound, or popup ad. We do not implement these annoying types of ads!

We need fund to operate the site, and almost all of it comes from our online advertising.

Please add electricalvoice.com to your ad blocking whitelist or disable your adblocking software.

×