Control System 7

Electrical Engineering MCQ Question Papers: Campus Placement

Subject: Control System 7

Part 1: List for questions and answers of Control System II

Q1. A first order system is initially at and subjected to a sudden input at t=0. Its output reaches 1.1 V in 4 sec and eventually reaches steady state of 2 V. Find the time constant?

a) 4 sec

b) 5 sec

c) 2 sec

d) 6 sec

Q2. A second order control system has a transfer function 16/(s² + 4s + 16). What is the time for the first overshoot?

a) 2p/v3 sec

b) p/v3 sec

c) p/2v3 sec

d) p/4v3 sec

Q3. Two identical first order systems have been cascaded non interactively. The unit step response of the systems will be

a) Over damped

b) Under damped

c) Critical damped

d) Un damped

Q4. A second order control system has a transfer function 16/(s² + 4s + 16). Find the settling time for 2% tolerance?

a) 10 sec

b) 5 sec

c) 4 sec

d) 2 sec

Q5. Settling time for 5% tolerance band is ———-

a) 3T

b) 4T

c) 5T

d) 2T

Q6. The optimum values of damping ration is ————–

a) 0.9 to 1.1

b) 0.3 to 5

c) 0.3 to 0.7

d) to 2

Q7. For the polynomial P(s) = 2s^5 + s^4 + 4s^3 + 2s^2 + 3s + 15, number of roots which lie in the right half of s-plane is

a) 4

b) 2

c) 3

d) 1

Q8. For the polynomial P(s) = s^4 + 8s^3 + 18s^² + 16s +5, find the number of roots which lie on the right half of s-plane?

a) 1

b) 2

c) 4

d) 0

Q9. The system having characteristic equation s^4 + 2s^3 + 3s² + 2s + k = 0 is used to be an oscillator. What is the value of k?

a) 1

b) 2

c) 3

d) 4

Q10. unit step response of the system is 1 – e-t(1+t). Which is the system?

a) Unstable

b) Stable

c) Oscillatory

d) Critically stable

Q11. The angle condition is used for checking whether any point lies on root locus or not is………

a) ± (2q + 1) 180°

b) ± (2q) 180°

c) ± (2q + 1) 360°

d) ± (2q) 360°

Q12. The magnitude condition for root locus is ………………

a) |G(s)H(s)| = 0

b) |G(s)H(s)| = 2

c) |G(s)H(s)| = 1

d) |G(s)H(s)| = 8

Q13. A unity feedback control system has an open loop transfer function G(s) = k/(s(s² + 7s + 12) The gain k for which s = -1 + j1 will lie on the root locus of the system is

a) 4

b) 6.5

c) 5

d) 10

Q14. Let P = Number of open loop poles and Z = Number of open loop zeros and P>Z, find the number of branches terminating at 8 ?

a) Z

b) P-Z

c) P

d) any of the above

Q15. The characteristic equation of a control system is give by s(s + 4)(s² + 2s + 1) + k(s + 1) =0 What are the angles of asymptotes for the root loci for k = 0?

a) 0°, 120°, 240°

b) 0°, 180°, 300°

c) 60°, 180°, 300°

d) 120°, 180°, 240°

Q16. The characteristic equation of a control system is give by s(s + 4)(s² + 2s + 1) + k(s + 1) =0. Find the angle between the asymptotes?

a) 60°

b) 360°

c) 120°

d) 180°

Q17. Which of the following statements is/are true?

a) Centroid may be a part of root locus

b) Centroid may not be a part of root locus

c) Both 1 and 2

d) Nether 1 nor 2

Q18. The characteristic equation of a feedback control system is given by s³ + 5s² + (k + 6)s + k = 0. In the root loci diagram, the asymptotes of the root loci for large ‘k’ meet at a point in the s-plane whose coordinates are

a) (2,0)

b) (-2,0)

c) (-1,0)

d) (1,0)

Q19. A control system has open loop transfer function G(S) = k/(s(s+4)(s+6)). Break away point is lies between

a) 0 and -4

b) 0 and 4

c) -4 and -6

d) any of the above

Q20. A control system has open loop transfer function G(s) = k/(s(s + 2). Find the break away point?

a) -1

b) 1

c) -2

d) 2

Part 1: List for questions and answers of Control System II