Control System Questions and Answers - Concept of Stability Part-2

1. Roots on the imaginary axis makes the system :
a) Stable
b) Unstable
c) Marginally stable
d) Linear

Answer: c
Explanation:Roots on the imaginary axis makes the system marginally stable.

2. If the roots of the have negative real parts then the response is ____________
a) Stable
b) Unstable
c) Marginally stable
d) Bounded

Answer: d
Explanation: If the roots of the have negative real parts then the response is bounded and eventually decreases to zero.

3. If root of the characteristic equation has positive real part the system is :
a) Stable
b) Unstable
c) Marginally stable
d) Linear

Answer: b
Explanation: The impulse response of the system is infinite when the roots of the characteristic equation has positive real part.

4. A linear system can be classified as :
a) Absolutely stable
b) Conditionally stable
c) Unstable
d) All of the mentioned

Answer: d
Explanation: A system can be stable, unstable and conditionally stable also.

5. ___________ is a quantitative measure of how fast the transients die out in the system.
a) Absolutely stable
b) Conditionally stable
c) Unstable
d) Relative Stability

Answer: d
Explanation: Relative Stability may be measured by relative settling times of each root or pair of roots.

6. The techniques of linear system can be used in the non-linear system entirely:
a) True
b) False

Answer: b
Explanation: The techniques of the linear system cannot be entirely used in the non-linear system as they are differentiated by this way only.

7. The disadvantages of the linear system are:
a) The constraints on the linear operation over wide range demands unnecessarily high quality.
b) The restriction to the linear theory may inhibit the designer’s curiosity to deliberately introduce the non-linear components.
c) Practically systems are non-linear
d) All of the mentioned

Answer: d
Explanation: Linear system impose certain restrictions as the components cost is very high and it will cause restriction to operate the otherwise linear components in non-linear region with a view to improve system response.

8. System non-linearities are taken account by:
a) Analytical
b) Graphical and numerical techniques
c) Both a and b
d) None of the mentioned

Answer: c
Explanation: Systems non-linearities are taken into account by the analytical, graphical and numerical technique

9. The superposition theorem is :
a) Homogeneity
b) Additivity
c) Combination of homogeneity and additivity
d) Applied to non-linear systems

Answer: c
Explanation: Superposition theorem applies to linear system only and it refers to the additivity and homogeneity

10. The standard test signal can be applied to give output to:
a) Linear systems
b) Non-linear systems
c) Time variant systems
d) Time invariant systems

Answer: a
Explanation: For linear systems the standard test signals can be applied to give the desired output