MCQOPTIONS
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MCQOPTIONS
This section includes 58 Mcqs, each offering curated multiple-choice questions to sharpen your Control Systems knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
How can the steady state error can be reduced? |
| A. | By decreasing the type of the system |
| B. | By increasing system gain |
| C. | By decreasing the static error constant |
| D. | By increasing the input |
| Answer» E. | |
| 2. |
In second order system gain margin is : |
| A. | Zero value |
| B. | Finite value |
| C. | Infinite value |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 3. |
The stability of the linear system: |
| A. | Determined by the location of the poles |
| B. | Dependent entirely of whether or the system is driven |
| C. | The stability of the undriven linear system is dependent on the magnitude of the final initial state. |
| D. | Stability cannot be determined by the open loop poles |
| Answer» B. Dependent entirely of whether or the system is driven | |
| 4. |
Determine the condition for the stability of unity feedback control system whose open loop transfer function is given byG(s) = 2e-st/s(s+2) |
| A. | T >1 |
| B. | T <0 |
| C. | T <1 |
| D. | T >0 |
| Answer» D. T >0 | |
| 5. |
The characteristic equation of a feedback control system is s3+Ks2+9s+18. When the system is marginally stable, the frequency of the sustained oscillation: |
| A. | 1 |
| B. | 1.414 |
| C. | 1.732 |
| D. | 3 |
| Answer» E. | |
| 6. |
If the roots of the have negative real parts then the response is ____________ |
| A. | Stable |
| B. | Unstable |
| C. | Marginally stable |
| D. | Bounded |
| Answer» E. | |
| 7. |
None of the coefficients can be zero or negative unless one of the following occurs: |
| A. | One or more roots have positive real parts |
| B. | A root at origin |
| C. | Presence of root at the imaginary axis |
| D. | All of the mentioned |
| Answer» E. | |
| 8. |
The open loop transfer functions with unity feedback are given below for different systems.Among these systems the unstable system is |
| A. | G(s) =2/s+2 |
| B. | G(s) =2/s(s+2) |
| C. | G(s) =2/(s+2)s^2 |
| D. | G(s) =2(s+1)/s(s+2) |
| Answer» D. G(s) =2(s+1)/s(s+2) | |
| 9. |
Consider the following statement: |
| A. | A system is said to be stable if its output is bounded for any input |
| B. | A system is said to be stable if all the roots of the characteristic equation lie on the left half of the s plane. |
| C. | A system is said to be stable if all the roots of the characteristic equation have negative real parts. |
| D. | A second order system is always stable for finite values of open loop gain |
| Answer» B. A system is said to be stable if all the roots of the characteristic equation lie on the left half of the s plane. | |
| 10. |
Non-linear elements may exhibit___________ |
| A. | Linear systems |
| B. | Non-linear systems |
| C. | Limit cycles |
| D. | Time invariant systems |
| Answer» D. Time invariant systems | |
| 11. |
Determine the value of K such that roots of characteristic equation given below lies to the left of the line s = -1. s3+10s2+18s+K. |
| A. | K>16 and K<9 |
| B. | K<16 |
| C. | 9<K<16 |
| D. | K<9 |
| Answer» D. K<9 | |
| 12. |
Roots on the imaginary axis makes the system : |
| A. | Stable |
| B. | Unstable |
| C. | Marginally stable |
| D. | Linear |
| Answer» D. Linear | |
| 13. |
Consider a characteristic equation, s4+3s3+5s2+6s+k+10=0. The condition for stability is |
| A. | K>5 |
| B. | -10<K |
| C. | K>-4 |
| D. | -10<K<-4 |
| Answer» E. | |
| 14. |
A system with unity feedback having open loop transfer function as G(s) = K(s+1)/s3+as2+2s+1. What values of 'K' and 'a' should be chosen so that the system oscillates ? |
| A. | K =2, a =1 |
| B. | K =2, a =0.75 |
| C. | K =4, a =1 |
| D. | K =4, a =0.75 |
| Answer» C. K =4, a =1 | |
| 15. |
Routh Hurwitz criterion cannot be applied when the characteristic equation of the system containing coefficient's which is/are |
| A. | Exponential function of s |
| B. | Sinusoidal function of s |
| C. | Complex |
| D. | Exponential and sinusoidal function of s and complex |
| Answer» E. | |
| 16. |
The polynomial s4+Ks3+s2+s+1=0 the range of K for stability is _____________ |
| A. | K>5 |
| B. | -10<K |
| C. | K>-4 |
| D. | K-1>0 |
| Answer» E. | |
| 17. |
Roots with higher multiplicity on the imaginary axis makes the system : |
| A. | Absolutely stable |
| B. | Unstable |
| C. | Linear |
| D. | Stable |
| Answer» C. Linear | |
| 18. |
The characteristic equation of a system is given by3s4+10s3+5s2+2=0. This system is: |
| A. | Stable |
| B. | Marginally stable |
| C. | Unstable |
| D. | Linear |
| Answer» D. Linear | |
| 19. |
The necessary condition of stability are: |
| A. | Coefficient of characteristic equation must be real and have the same sign |
| B. | Coefficient of characteristic equation must be non-zero |
| C. | Both of the mentioned |
| D. | Coefficient of characteristic equation must be zero |
| Answer» D. Coefficient of characteristic equation must be zero | |
| 20. |
The necessary condition for the stability of the linear system is that all the coefficients of characteristic equation 1+G(s)H(s) =0, be real and have the : |
| A. | Positive sign |
| B. | Negative sign |
| C. | Same sign |
| D. | Both positive and negative |
| Answer» D. Both positive and negative | |
| 21. |
The roots of the transfer function do not have any effect on the stability of the system. |
| A. | True |
| B. | False |
| Answer» C. | |
| 22. |
Assertion (A): Routh criterion is in terms of array formulation, which is more convenient to handle.Reason (R): This method is used to investigate the method of stability of higher order systems. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true and R is not correct explanation of A |
| C. | A is true but R is false |
| D. | A is False but R is true |
| Answer» C. A is true but R is false | |
| 23. |
In non-linear system stability is : |
| A. | Dependent on the input |
| B. | Independent on initial state |
| C. | Independent on input |
| D. | Dependent on input and initial state. |
| Answer» E. | |
| 24. |
For making an unstable system stable: |
| A. | Gain of the system should be increased |
| B. | Gain of the system should be decreased |
| C. | The number of zeroes to the loop transfer function should be increased |
| D. | The number of poles to the loop transfer function should be increased |
| Answer» C. The number of zeroes to the loop transfer function should be increased | |
| 25. |
Determine the stability of closed loop control system whose characteristic equation iss5+s4+2s3+2s2+11s+10=0. |
| A. | Stable |
| B. | Marginally stable |
| C. | Unstable |
| D. | None of the mentioned |
| Answer» C. Unstable | |
| 26. |
For non-linear systems the equation for damping factor as in linear system is called__________ |
| A. | Krasovskii's equation |
| B. | Vander Pol's equation |
| C. | Constant method |
| D. | Non-variable gradient equation |
| Answer» C. Constant method | |
| 27. |
Liapunov stability analysis is different from the classical theories approach of stability. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 28. |
If the Liapunov's function cannot be found then the system is: |
| A. | Stable |
| B. | Unstable |
| C. | Conditionally stable |
| D. | Marginally stable |
| Answer» C. Conditionally stable | |
| 29. |
In polar plots, if a pole is added at the origin, what would be the value of the magnitude at Ω = 0? |
| A. | Zero |
| B. | Infinity |
| C. | Unity |
| D. | Unpredictable |
| Answer» C. Unity | |
| 30. |
The visual analogy of the Liapunov energy description is: |
| A. | Ellipse |
| B. | Circle |
| C. | Square |
| D. | Rectangle |
| Answer» B. Circle | |
| 31. |
The system is stable at origin if for every initial state which is sufficiently close to the origin remains near the origin for all t then the system is : |
| A. | Asymptotically stable |
| B. | Asymptotically stable in the large |
| C. | Stable |
| D. | Unstable |
| Answer» D. Unstable | |
| 32. |
The systems with equation such as dx/dt =F (x) are called: |
| A. | Stable systems |
| B. | Control systems |
| C. | Autonomous systems |
| D. | Unstable control system |
| Answer» D. Unstable control system | |
| 33. |
The non-linear system |
| A. | Have one equilibrium state |
| B. | Their behavior determines the qualitative behavior of the s-plane |
| C. | System behavior for small deviations about the equilibrium point may be different from the large deviation |
| D. | Both a and b |
| Answer» D. Both a and b | |
| 34. |
Liapunov's stability for non-linear system is same as the Routh Hurwitz criteria for the linear system. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 35. |
Liapunov's stability analysis is for the : |
| A. | LTI system |
| B. | Time variant system |
| C. | Non-linear system |
| D. | Linear system |
| Answer» D. Linear system | |
| 36. |
If x (t) approaches near the origin as t tends to infinity then the system is : |
| A. | Asymptotically stable |
| B. | Asymptotically stable in the large |
| C. | Stable |
| D. | Unstable |
| Answer» B. Asymptotically stable in the large | |
| 37. |
It is difficult to form Liapunov's function for: |
| A. | Linear system |
| B. | Non-linear |
| C. | Time variant systems |
| D. | Time -invariant systems |
| Answer» C. Time variant systems | |
| 38. |
The method which provides considerable flexibility in finding the Liapunov's function is: |
| A. | Krasovskii's method |
| B. | Variable gradient method |
| C. | Constant method |
| D. | Non-variable gradient method |
| Answer» C. Constant method | |
| 39. |
The idea that the non-negative scalar functions of a system state can also answer the question of stability was given in Liapunov function: |
| A. | True |
| B. | False |
| Answer» B. False | |
| 40. |
The method of investigating the stability using Liapunov function as the ________________ |
| A. | Direct method |
| B. | Indirect method |
| C. | Not determined |
| D. | Always unstable |
| Answer» B. Indirect method | |
| 41. |
If the impulse response in absolutely integrable then the system is : |
| A. | Absolutely stable |
| B. | Unstable |
| C. | Linear |
| D. | Stable |
| Answer» B. Unstable | |
| 42. |
If a Nyquist plot of G (jω) H (jω) for a closed loop system passes through (-2, j0) point in GH plane, what would be the value of gain margin of the system in dB? |
| A. | 0 dB |
| B. | 2.0201 dB |
| C. | 4 dB |
| D. | 6.0205 dB |
| Answer» E. | |
| 43. |
If the system is represented by G(s) H(s) = k (s+7) / s (s +3) (s + 2), what would be its magnitude at ω = ∞? |
| A. | 0 |
| B. | ∞ |
| C. | 7/10 |
| D. | 21 |
| Answer» B. ∞ | |
| 44. |
A polar plot intersects the unit circle at a point making -45° to the negative real axis then the phase margin of the system is : |
| A. | -45° |
| B. | 45° |
| C. | 180°-45° |
| D. | 180°+45° |
| Answer» C. 180°-45° | |
| 45. |
Gain margin is: |
| A. | It is a factor by which the system gain can be increased to drive it to the verge of instability |
| B. | It is calculated at gain cross over frequency |
| C. | It is calculated at phase cross over frequency |
| D. | Both a and c |
| Answer» E. | |
| 46. |
Phase margin is: |
| A. | It is amount of additional phase lag at the gain cross over frequency required to bring the system to the verge of instability |
| B. | It is always positive for stable feedback systems |
| C. | It is calculated at gain cross over frequency |
| D. | All of the mentioned |
| Answer» E. | |
| 47. |
An underdamped second order system with negative damping will have the roots : |
| A. | On the negative real axis as roots |
| B. | On the left hand side of complex plane as complex roots |
| C. | On the right hand side of complex plane as complex conjugates |
| D. | On the positive real axis as real roots |
| Answer» D. On the positive real axis as real roots | |
| 48. |
Given a unity feedback system with G (s) =K/ s (s+4). What is the value of K for a damping ratio of 0.5? |
| A. | 1 |
| B. | 16 |
| C. | 4 |
| D. | 2 |
| Answer» C. 4 | |
| 49. |
Consider the system represented by the equation given below. What would be the total phase value at ω = 0?200/[s3 (s + 3) (s + 6) (s + 10)]. |
| A. | -90° |
| B. | -180° |
| C. | -270° |
| D. | -360° |
| Answer» D. -360° | |
| 50. |
The system with the open loop transfer function G(s) H(s) =1/s(s^2+s+1) has the gain margin of : |
| A. | -6 dB |
| B. | 0 dB |
| C. | 3.5 dB |
| D. | 6 dB |
| Answer» C. 3.5 dB | |